avutil/channel_layout: Add a new channel layout API

The new API is more extensible and allows for custom layouts.
More accurate information is exported, eg for decoders that do not
set a channel layout, lavc will not make one up for them.

Deprecate the old API working with just uint64_t bitmasks.

Expanded and completed by Vittorio Giovara <vittorio.giovara@gmail.com>
and James Almer <jamrial@gmail.com>.
Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>

3 files changed, 1086 insertions, 103 deletions

diff --git a/libavutil/channel_layout.c b/libavutil/channel_layout.c
index b9507b1bff..506604cc9f 100644
--- a/libavutil/channel_layout.c
+++ b/libavutil/channel_layout.c
@@ -32,6 +32,7 @@
 #include "common.h"
 #include "error.h"
 #include "macros.h"
+#include "opt.h"
 
 struct channel_name {
     const char *name;
@@ -39,81 +40,149 @@ struct channel_name {
 };
 
 static const struct channel_name channel_names[] = {
-     [0] = { "FL",        "front left"            },
-     [1] = { "FR",        "front right"           },
-     [2] = { "FC",        "front center"          },
-     [3] = { "LFE",       "low frequency"         },
-     [4] = { "BL",        "back left"             },
-     [5] = { "BR",        "back right"            },
-     [6] = { "FLC",       "front left-of-center"  },
-     [7] = { "FRC",       "front right-of-center" },
-     [8] = { "BC",        "back center"           },
-     [9] = { "SL",        "side left"             },
-    [10] = { "SR",        "side right"            },
-    [11] = { "TC",        "top center"            },
-    [12] = { "TFL",       "top front left"        },
-    [13] = { "TFC",       "top front center"      },
-    [14] = { "TFR",       "top front right"       },
-    [15] = { "TBL",       "top back left"         },
-    [16] = { "TBC",       "top back center"       },
-    [17] = { "TBR",       "top back right"        },
-    [29] = { "DL",        "downmix left"          },
-    [30] = { "DR",        "downmix right"         },
-    [31] = { "WL",        "wide left"             },
-    [32] = { "WR",        "wide right"            },
-    [33] = { "SDL",       "surround direct left"  },
-    [34] = { "SDR",       "surround direct right" },
-    [35] = { "LFE2",      "low frequency 2"       },
-    [36] = { "TSL",       "top side left"         },
-    [37] = { "TSR",       "top side right"        },
-    [38] = { "BFC",       "bottom front center"   },
-    [39] = { "BFL",       "bottom front left"     },
-    [40] = { "BFR",       "bottom front right"    },
+    [AV_CHAN_FRONT_LEFT           ] = { "FL",        "front left"            },
+    [AV_CHAN_FRONT_RIGHT          ] = { "FR",        "front right"           },
+    [AV_CHAN_FRONT_CENTER         ] = { "FC",        "front center"          },
+    [AV_CHAN_LOW_FREQUENCY        ] = { "LFE",       "low frequency"         },
+    [AV_CHAN_BACK_LEFT            ] = { "BL",        "back left"             },
+    [AV_CHAN_BACK_RIGHT           ] = { "BR",        "back right"            },
+    [AV_CHAN_FRONT_LEFT_OF_CENTER ] = { "FLC",       "front left-of-center"  },
+    [AV_CHAN_FRONT_RIGHT_OF_CENTER] = { "FRC",       "front right-of-center" },
+    [AV_CHAN_BACK_CENTER          ] = { "BC",        "back center"           },
+    [AV_CHAN_SIDE_LEFT            ] = { "SL",        "side left"             },
+    [AV_CHAN_SIDE_RIGHT           ] = { "SR",        "side right"            },
+    [AV_CHAN_TOP_CENTER           ] = { "TC",        "top center"            },
+    [AV_CHAN_TOP_FRONT_LEFT       ] = { "TFL",       "top front left"        },
+    [AV_CHAN_TOP_FRONT_CENTER     ] = { "TFC",       "top front center"      },
+    [AV_CHAN_TOP_FRONT_RIGHT      ] = { "TFR",       "top front right"       },
+    [AV_CHAN_TOP_BACK_LEFT        ] = { "TBL",       "top back left"         },
+    [AV_CHAN_TOP_BACK_CENTER      ] = { "TBC",       "top back center"       },
+    [AV_CHAN_TOP_BACK_RIGHT       ] = { "TBR",       "top back right"        },
+    [AV_CHAN_STEREO_LEFT          ] = { "DL",        "downmix left"          },
+    [AV_CHAN_STEREO_RIGHT         ] = { "DR",        "downmix right"         },
+    [AV_CHAN_WIDE_LEFT            ] = { "WL",        "wide left"             },
+    [AV_CHAN_WIDE_RIGHT           ] = { "WR",        "wide right"            },
+    [AV_CHAN_SURROUND_DIRECT_LEFT ] = { "SDL",       "surround direct left"  },
+    [AV_CHAN_SURROUND_DIRECT_RIGHT] = { "SDR",       "surround direct right" },
+    [AV_CHAN_LOW_FREQUENCY_2      ] = { "LFE2",      "low frequency 2"       },
+    [AV_CHAN_TOP_SIDE_LEFT        ] = { "TSL",       "top side left"         },
+    [AV_CHAN_TOP_SIDE_RIGHT       ] = { "TSR",       "top side right"        },
+    [AV_CHAN_BOTTOM_FRONT_CENTER  ] = { "BFC",       "bottom front center"   },
+    [AV_CHAN_BOTTOM_FRONT_LEFT    ] = { "BFL",       "bottom front left"     },
+    [AV_CHAN_BOTTOM_FRONT_RIGHT   ] = { "BFR",       "bottom front right"    },
 };
 
-static const char *get_channel_name(int channel_id)
+static const char *get_channel_name(enum AVChannel channel_id)
 {
-    if (channel_id < 0 || channel_id >= FF_ARRAY_ELEMS(channel_names))
+    if ((unsigned) channel_id >= FF_ARRAY_ELEMS(channel_names) ||
+        !channel_names[channel_id].name)
         return NULL;
     return channel_names[channel_id].name;
 }
 
-static const struct {
+void av_channel_name_bprint(AVBPrint *bp, enum AVChannel channel_id)
+{
+    if ((unsigned)channel_id < FF_ARRAY_ELEMS(channel_names))
+        av_bprintf(bp, "%s", channel_names[channel_id].name);
+    else if (channel_id == AV_CHAN_NONE)
+        av_bprintf(bp, "NONE");
+    else
+        av_bprintf(bp, "USR%d", channel_id);
+}
+
+int av_channel_name(char *buf, size_t buf_size, enum AVChannel channel_id)
+{
+    AVBPrint bp;
+
+    if (!buf && buf_size)
+        return AVERROR(EINVAL);
+
+    av_bprint_init_for_buffer(&bp, buf, buf_size);
+    av_channel_name_bprint(&bp, channel_id);
+
+    return bp.len;
+}
+
+void av_channel_description_bprint(AVBPrint *bp, enum AVChannel channel_id)
+{
+    if ((unsigned)channel_id < FF_ARRAY_ELEMS(channel_names))
+        av_bprintf(bp, "%s", channel_names[channel_id].description);
+    else
+        av_bprintf(bp, "user %d", channel_id);
+}
+
+int av_channel_description(char *buf, size_t buf_size, enum AVChannel channel_id)
+{
+    AVBPrint bp;
+
+    if (!buf && buf_size)
+        return AVERROR(EINVAL);
+
+    av_bprint_init_for_buffer(&bp, buf, buf_size);
+    av_channel_description_bprint(&bp, channel_id);
+
+    return bp.len;
+}
+
+enum AVChannel av_channel_from_string(const char *str)
+{
+    int i;
+    char *endptr = (char *)str;
+    enum AVChannel id = AV_CHAN_NONE;
+    for (i = 0; i < FF_ARRAY_ELEMS(channel_names); i++) {
+        if (channel_names[i].name && !strcmp(str, channel_names[i].name))
+            return i;
+    }
+    if (!strncmp(str, "USR", 3)) {
+        const char *p = str + 3;
+        id = strtol(p, &endptr, 0);
+    }
+    if (id >= 0 && !*endptr)
+        return id;
+
+    return AV_CHAN_NONE;
+}
+
+struct channel_layout_name {
     const char *name;
-    int         nb_channels;
-    uint64_t     layout;
-} channel_layout_map[] = {
-    { "mono",        1,  AV_CH_LAYOUT_MONO },
-    { "stereo",      2,  AV_CH_LAYOUT_STEREO },
-    { "2.1",         3,  AV_CH_LAYOUT_2POINT1 },
-    { "3.0",         3,  AV_CH_LAYOUT_SURROUND },
-    { "3.0(back)",   3,  AV_CH_LAYOUT_2_1 },
-    { "4.0",         4,  AV_CH_LAYOUT_4POINT0 },
-    { "quad",        4,  AV_CH_LAYOUT_QUAD },
-    { "quad(side)",  4,  AV_CH_LAYOUT_2_2 },
-    { "3.1",         4,  AV_CH_LAYOUT_3POINT1 },
-    { "5.0",         5,  AV_CH_LAYOUT_5POINT0_BACK },
-    { "5.0(side)",   5,  AV_CH_LAYOUT_5POINT0 },
-    { "4.1",         5,  AV_CH_LAYOUT_4POINT1 },
-    { "5.1",         6,  AV_CH_LAYOUT_5POINT1_BACK },
-    { "5.1(side)",   6,  AV_CH_LAYOUT_5POINT1 },
-    { "6.0",         6,  AV_CH_LAYOUT_6POINT0 },
-    { "6.0(front)",  6,  AV_CH_LAYOUT_6POINT0_FRONT },
-    { "hexagonal",   6,  AV_CH_LAYOUT_HEXAGONAL },
-    { "6.1",         7,  AV_CH_LAYOUT_6POINT1 },
-    { "6.1(back)",   7,  AV_CH_LAYOUT_6POINT1_BACK },
-    { "6.1(front)",  7,  AV_CH_LAYOUT_6POINT1_FRONT },
-    { "7.0",         7,  AV_CH_LAYOUT_7POINT0 },
-    { "7.0(front)",  7,  AV_CH_LAYOUT_7POINT0_FRONT },
-    { "7.1",         8,  AV_CH_LAYOUT_7POINT1 },
-    { "7.1(wide)",   8,  AV_CH_LAYOUT_7POINT1_WIDE_BACK },
-    { "7.1(wide-side)",   8,  AV_CH_LAYOUT_7POINT1_WIDE },
-    { "octagonal",   8,  AV_CH_LAYOUT_OCTAGONAL },
-    { "hexadecagonal", 16, AV_CH_LAYOUT_HEXADECAGONAL },
-    { "downmix",     2,  AV_CH_LAYOUT_STEREO_DOWNMIX, },
-    { "22.2",          24, AV_CH_LAYOUT_22POINT2, },
+    AVChannelLayout layout;
 };
 
+static const struct channel_layout_name channel_layout_map[] = {
+    { "mono",           AV_CHANNEL_LAYOUT_MONO                },
+    { "stereo",         AV_CHANNEL_LAYOUT_STEREO              },
+    { "stereo",         AV_CHANNEL_LAYOUT_STEREO_DOWNMIX      },
+    { "2.1",            AV_CHANNEL_LAYOUT_2POINT1             },
+    { "3.0",            AV_CHANNEL_LAYOUT_SURROUND            },
+    { "3.0(back)",      AV_CHANNEL_LAYOUT_2_1                 },
+    { "4.0",            AV_CHANNEL_LAYOUT_4POINT0             },
+    { "quad",           AV_CHANNEL_LAYOUT_QUAD                },
+    { "quad(side)",     AV_CHANNEL_LAYOUT_2_2                 },
+    { "3.1",            AV_CHANNEL_LAYOUT_3POINT1             },
+    { "5.0",            AV_CHANNEL_LAYOUT_5POINT0_BACK        },
+    { "5.0(side)",      AV_CHANNEL_LAYOUT_5POINT0             },
+    { "4.1",            AV_CHANNEL_LAYOUT_4POINT1             },
+    { "5.1",            AV_CHANNEL_LAYOUT_5POINT1_BACK        },
+    { "5.1(side)",      AV_CHANNEL_LAYOUT_5POINT1             },
+    { "6.0",            AV_CHANNEL_LAYOUT_6POINT0             },
+    { "6.0(front)",     AV_CHANNEL_LAYOUT_6POINT0_FRONT       },
+    { "hexagonal",      AV_CHANNEL_LAYOUT_HEXAGONAL           },
+    { "6.1",            AV_CHANNEL_LAYOUT_6POINT1             },
+    { "6.1(back)",      AV_CHANNEL_LAYOUT_6POINT1_BACK        },
+    { "6.1(front)",     AV_CHANNEL_LAYOUT_6POINT1_FRONT       },
+    { "7.0",            AV_CHANNEL_LAYOUT_7POINT0             },
+    { "7.0(front)",     AV_CHANNEL_LAYOUT_7POINT0_FRONT       },
+    { "7.1",            AV_CHANNEL_LAYOUT_7POINT1             },
+    { "7.1(wide)",      AV_CHANNEL_LAYOUT_7POINT1_WIDE_BACK   },
+    { "7.1(wide-side)", AV_CHANNEL_LAYOUT_7POINT1_WIDE        },
+    { "octagonal",      AV_CHANNEL_LAYOUT_OCTAGONAL           },
+    { "hexadecagonal",  AV_CHANNEL_LAYOUT_HEXADECAGONAL       },
+    { "downmix",        AV_CHANNEL_LAYOUT_STEREO_DOWNMIX,     },
+    { "22.2",           AV_CHANNEL_LAYOUT_22POINT2,           },
+};
+
+#if FF_API_OLD_CHANNEL_LAYOUT
+FF_DISABLE_DEPRECATION_WARNINGS
 static uint64_t get_channel_layout_single(const char *name, int name_len)
 {
     int i;
@@ -123,7 +192,7 @@ static uint64_t get_channel_layout_single(const char *name, int name_len)
     for (i = 0; i < FF_ARRAY_ELEMS(channel_layout_map); i++) {
         if (strlen(channel_layout_map[i].name) == name_len &&
             !memcmp(channel_layout_map[i].name, name, name_len))
-            return channel_layout_map[i].layout;
+            return channel_layout_map[i].layout.u.mask;
     }
     for (i = 0; i < FF_ARRAY_ELEMS(channel_names); i++)
         if (channel_names[i].name &&
@@ -191,8 +260,8 @@ void av_bprint_channel_layout(struct AVBPrint *bp,
         nb_channels = av_get_channel_layout_nb_channels(channel_layout);
 
     for (i = 0; i < FF_ARRAY_ELEMS(channel_layout_map); i++)
-        if (nb_channels    == channel_layout_map[i].nb_channels &&
-            channel_layout == channel_layout_map[i].layout) {
+        if (nb_channels    == channel_layout_map[i].layout.nb_channels &&
+            channel_layout == channel_layout_map[i].layout.u.mask) {
             av_bprintf(bp, "%s", channel_layout_map[i].name);
             return;
         }
@@ -233,8 +302,8 @@ int av_get_channel_layout_nb_channels(uint64_t channel_layout)
 int64_t av_get_default_channel_layout(int nb_channels) {
     int i;
     for (i = 0; i < FF_ARRAY_ELEMS(channel_layout_map); i++)
-        if (nb_channels == channel_layout_map[i].nb_channels)
-            return channel_layout_map[i].layout;
+        if (nb_channels == channel_layout_map[i].layout.nb_channels)
+            return channel_layout_map[i].layout.u.mask;
     return 0;
 }
 
@@ -289,7 +358,459 @@ int av_get_standard_channel_layout(unsigned index, uint64_t *layout,
 {
     if (index >= FF_ARRAY_ELEMS(channel_layout_map))
         return AVERROR_EOF;
-    if (layout) *layout = channel_layout_map[index].layout;
+    if (layout) *layout = channel_layout_map[index].layout.u.mask;
     if (name)   *name   = channel_layout_map[index].name;
     return 0;
 }
+FF_ENABLE_DEPRECATION_WARNINGS
+#endif
+
+int av_channel_layout_from_mask(AVChannelLayout *channel_layout,
+                                uint64_t mask)
+{
+    if (!mask)
+        return AVERROR(EINVAL);
+
+    channel_layout->order       = AV_CHANNEL_ORDER_NATIVE;
+    channel_layout->nb_channels = av_popcount64(mask);
+    channel_layout->u.mask      = mask;
+
+    return 0;
+}
+
+int av_channel_layout_from_string(AVChannelLayout *channel_layout,
+                                  const char *str)
+{
+    int i;
+    int channels = 0, nb_channels = 0, native = 1;
+    enum AVChannel highest_channel = AV_CHAN_NONE;
+    const char *dup;
+    char *chlist, *end;
+    uint64_t mask = 0;
+
+    /* channel layout names */
+    for (i = 0; i < FF_ARRAY_ELEMS(channel_layout_map); i++) {
+        if (channel_layout_map[i].name && !strcmp(str, channel_layout_map[i].name)) {
+            *channel_layout = channel_layout_map[i].layout;
+            return 0;
+        }
+    }
+
+    chlist = av_strdup(str);
+    if (!chlist)
+        return AVERROR(ENOMEM);
+
+    /* channel names */
+    av_sscanf(str, "%d channels (%[^)]", &nb_channels, chlist);
+    end = strchr(str, ')');
+
+    dup = chlist;
+    while (*dup) {
+        char *channel, *chname;
+        int ret = av_opt_get_key_value(&dup, "@", "+", AV_OPT_FLAG_IMPLICIT_KEY, &channel, &chname);
+        if (ret < 0) {
+            av_free(chlist);
+            return ret;
+        }
+        if (*dup)
+            dup++; // skip separator
+        if (channel && !*channel)
+            av_freep(&channel);
+        for (i = 0; i < FF_ARRAY_ELEMS(channel_names); i++) {
+            if (channel_names[i].name && !strcmp(channel ? channel : chname, channel_names[i].name)) {
+                if (channel || i < highest_channel || mask & (1ULL << i))
+                    native = 0; // Not a native layout, use a custom one
+                highest_channel = i;
+                mask |= 1ULL << i;
+                break;
+            }
+        }
+
+        if (!channel && i >= FF_ARRAY_ELEMS(channel_names)) {
+            char *endptr = chname;
+            enum AVChannel id = AV_CHAN_NONE;
+
+            if (!strncmp(chname, "USR", 3)) {
+                const char *p = chname + 3;
+                id = strtol(p, &endptr, 0);
+            }
+            if (id < 0 || *endptr) {
+                native = 0; // Unknown channel name
+                channels = 0;
+                mask = 0;
+                av_free(chname);
+                break;
+            }
+            if (id > 63)
+                native = 0; // Not a native layout, use a custom one
+            else {
+                if (id < highest_channel || mask & (1ULL << id))
+                    native = 0; // Not a native layout, use a custom one
+                highest_channel = id;
+                mask |= 1ULL << id;
+            }
+        }
+        channels++;
+        av_free(channel);
+        av_free(chname);
+    }
+
+    if (mask && native) {
+        av_free(chlist);
+        if (nb_channels && ((nb_channels != channels) || (!end || *++end)))
+            return AVERROR(EINVAL);
+        av_channel_layout_from_mask(channel_layout, mask);
+        return 0;
+    }
+
+    /* custom layout of channel names */
+    if (channels && !native) {
+        int idx = 0;
+
+        if (nb_channels && ((nb_channels != channels) || (!end || *++end))) {
+            av_free(chlist);
+            return AVERROR(EINVAL);
+        }
+
+        channel_layout->u.map = av_calloc(channels, sizeof(*channel_layout->u.map));
+        if (!channel_layout->u.map) {
+            av_free(chlist);
+            return AVERROR(ENOMEM);
+        }
+
+        channel_layout->order = AV_CHANNEL_ORDER_CUSTOM;
+        channel_layout->nb_channels = channels;
+
+        dup = chlist;
+        while (*dup) {
+            char *channel, *chname;
+            int ret = av_opt_get_key_value(&dup, "@", "+", AV_OPT_FLAG_IMPLICIT_KEY, &channel, &chname);
+            if (ret < 0) {
+                av_freep(&channel_layout->u.map);
+                av_free(chlist);
+                return ret;
+            }
+            if (*dup)
+                dup++; // skip separator
+            for (i = 0; i < FF_ARRAY_ELEMS(channel_names); i++) {
+                if (channel_names[i].name && !strcmp(channel ? channel : chname, channel_names[i].name)) {
+                    channel_layout->u.map[idx].id = i;
+                    if (channel)
+                        av_strlcpy(channel_layout->u.map[idx].name, chname, sizeof(channel_layout->u.map[idx].name));
+                    idx++;
+                    break;
+                }
+            }
+            if (i >= FF_ARRAY_ELEMS(channel_names)) {
+                const char *p = (channel ? channel : chname) + 3;
+                channel_layout->u.map[idx].id = strtol(p, NULL, 0);
+                if (channel)
+                    av_strlcpy(channel_layout->u.map[idx].name, chname, sizeof(channel_layout->u.map[idx].name));
+                idx++;
+            }
+            av_free(channel);
+            av_free(chname);
+        }
+
+        return 0;
+    }
+    av_freep(&chlist);
+
+    errno = 0;
+    mask = strtoull(str, &end, 0);
+
+    /* channel layout mask */
+    if (!errno && !*end && !strchr(str, '-') && mask) {
+        av_channel_layout_from_mask(channel_layout, mask);
+        return 0;
+    }
+
+    errno = 0;
+    channels = strtol(str, &end, 10);
+
+    /* number of channels */
+    if (!errno && !strcmp(end, "c") && channels > 0) {
+        av_channel_layout_default(channel_layout, channels);
+        if (channel_layout->order == AV_CHANNEL_ORDER_NATIVE)
+            return 0;
+    }
+
+    /* number of unordered channels */
+    if (!errno && (!strcmp(end, "C") || !strcmp(end, " channels"))
+        && channels > 0) {
+        channel_layout->order = AV_CHANNEL_ORDER_UNSPEC;
+        channel_layout->nb_channels = channels;
+        return 0;
+    }
+
+    return AVERROR(EINVAL);
+}
+
+void av_channel_layout_uninit(AVChannelLayout *channel_layout)
+{
+    if (channel_layout->order == AV_CHANNEL_ORDER_CUSTOM)
+        av_freep(&channel_layout->u.map);
+    memset(channel_layout, 0, sizeof(*channel_layout));
+}
+
+int av_channel_layout_copy(AVChannelLayout *dst, const AVChannelLayout *src)
+{
+    av_channel_layout_uninit(dst);
+    *dst = *src;
+    if (src->order == AV_CHANNEL_ORDER_CUSTOM) {
+        dst->u.map = av_malloc_array(src->nb_channels, sizeof(*dst->u.map));
+        if (!dst->u.map)
+            return AVERROR(ENOMEM);
+        memcpy(dst->u.map, src->u.map, src->nb_channels * sizeof(*src->u.map));
+    }
+    return 0;
+}
+
+int av_channel_layout_describe_bprint(const AVChannelLayout *channel_layout,
+                                      AVBPrint *bp)
+{
+    int i;
+
+    switch (channel_layout->order) {
+    case AV_CHANNEL_ORDER_NATIVE:
+        for (i = 0; i < FF_ARRAY_ELEMS(channel_layout_map); i++)
+            if (channel_layout->u.mask == channel_layout_map[i].layout.u.mask) {
+                av_bprintf(bp, "%s", channel_layout_map[i].name);
+                return 0;
+            }
+        // fall-through
+    case AV_CHANNEL_ORDER_CUSTOM:
+        if (channel_layout->nb_channels)
+            av_bprintf(bp, "%d channels (", channel_layout->nb_channels);
+        for (i = 0; i < channel_layout->nb_channels; i++) {
+            enum AVChannel ch = av_channel_layout_channel_from_index(channel_layout, i);
+            const char *channel = get_channel_name(ch);
+
+            if (i)
+                av_bprintf(bp, "+");
+            if (channel)
+                av_bprintf(bp, "%s", channel);
+            else
+                av_bprintf(bp, "USR%d", ch);
+            if (channel_layout->order == AV_CHANNEL_ORDER_CUSTOM &&
+                channel_layout->u.map[i].name[0])
+                av_bprintf(bp, "@%s", channel_layout->u.map[i].name);
+        }
+        if (channel_layout->nb_channels) {
+            av_bprintf(bp, ")");
+            return 0;
+        }
+        // fall-through
+    case AV_CHANNEL_ORDER_UNSPEC:
+        av_bprintf(bp, "%d channels", channel_layout->nb_channels);
+        return 0;
+    default:
+        return AVERROR(EINVAL);
+    }
+}
+
+int av_channel_layout_describe(const AVChannelLayout *channel_layout,
+                               char *buf, size_t buf_size)
+{
+    AVBPrint bp;
+    int ret;
+
+    if (!buf && buf_size)
+        return AVERROR(EINVAL);
+
+    av_bprint_init_for_buffer(&bp, buf, buf_size);
+    ret = av_channel_layout_describe_bprint(channel_layout, &bp);
+    if (ret < 0)
+        return ret;
+
+    return bp.len;
+}
+
+enum AVChannel
+av_channel_layout_channel_from_index(const AVChannelLayout *channel_layout,
+                                     unsigned int idx)
+{
+    int i;
+
+    if (idx >= channel_layout->nb_channels)
+        return AV_CHAN_NONE;
+
+    switch (channel_layout->order) {
+    case AV_CHANNEL_ORDER_CUSTOM:
+        return channel_layout->u.map[idx].id;
+    case AV_CHANNEL_ORDER_NATIVE:
+        for (i = 0; i < 64; i++) {
+            if ((1ULL << i) & channel_layout->u.mask && !idx--)
+                return i;
+        }
+    default:
+        return AV_CHAN_NONE;
+    }
+}
+
+enum AVChannel
+av_channel_layout_channel_from_string(const AVChannelLayout *channel_layout,
+                                      const char *str)
+{
+    int index = av_channel_layout_index_from_string(channel_layout, str);
+
+    if (index < 0)
+        return AV_CHAN_NONE;
+
+    return av_channel_layout_channel_from_index(channel_layout, index);
+}
+
+int av_channel_layout_index_from_channel(const AVChannelLayout *channel_layout,
+                                         enum AVChannel channel)
+{
+    int i;
+
+    if (channel == AV_CHAN_NONE)
+        return AVERROR(EINVAL);
+
+    switch (channel_layout->order) {
+    case AV_CHANNEL_ORDER_CUSTOM:
+        for (i = 0; i < channel_layout->nb_channels; i++)
+            if (channel_layout->u.map[i].id == channel)
+                return i;
+        return AVERROR(EINVAL);
+    case AV_CHANNEL_ORDER_NATIVE: {
+        uint64_t mask = channel_layout->u.mask;
+        if ((unsigned)channel > 63 || !(mask & (1ULL << channel)))
+            return AVERROR(EINVAL);
+        mask &= (1ULL << channel) - 1;
+        return av_popcount64(mask);
+        }
+    default:
+        return AVERROR(EINVAL);
+    }
+}
+
+int av_channel_layout_index_from_string(const AVChannelLayout *channel_layout,
+                                        const char *str)
+{
+    char *chname;
+    enum AVChannel ch = AV_CHAN_NONE;
+
+    switch (channel_layout->order) {
+    case AV_CHANNEL_ORDER_CUSTOM:
+        chname = strstr(str, "@");
+        if (chname) {
+            char buf[16];
+            chname++;
+            av_strlcpy(buf, str, FFMIN(sizeof(buf), chname - str));
+            if (!*chname)
+                chname = NULL;
+            ch = av_channel_from_string(buf);
+            if (ch == AV_CHAN_NONE && *buf)
+                return AVERROR(EINVAL);
+        }
+        for (int i = 0; chname && i < channel_layout->nb_channels; i++) {
+            if (!strcmp(chname, channel_layout->u.map[i].name) &&
+                (ch == AV_CHAN_NONE || ch == channel_layout->u.map[i].id))
+                return i;
+        }
+        // fall-through
+    case AV_CHANNEL_ORDER_NATIVE:
+        ch = av_channel_from_string(str);
+        if (ch == AV_CHAN_NONE)
+            return AVERROR(EINVAL);
+        return av_channel_layout_index_from_channel(channel_layout, ch);
+    }
+
+    return AVERROR(EINVAL);
+}
+
+int av_channel_layout_check(const AVChannelLayout *channel_layout)
+{
+    if (channel_layout->nb_channels <= 0)
+        return 0;
+
+    switch (channel_layout->order) {
+    case AV_CHANNEL_ORDER_NATIVE:
+        return av_popcount64(channel_layout->u.mask) == channel_layout->nb_channels;
+    case AV_CHANNEL_ORDER_CUSTOM:
+        if (!channel_layout->u.map)
+            return 0;
+        for (int i = 0; i < channel_layout->nb_channels; i++) {
+            if (channel_layout->u.map[i].id == AV_CHAN_NONE)
+                return 0;
+        }
+        return 1;
+    case AV_CHANNEL_ORDER_UNSPEC:
+        return 1;
+    default:
+        return 0;
+    }
+}
+
+int av_channel_layout_compare(const AVChannelLayout *chl, const AVChannelLayout *chl1)
+{
+    int i;
+
+    /* different channel counts -> not equal */
+    if (chl->nb_channels != chl1->nb_channels)
+        return 1;
+
+    /* if only one is unspecified -> not equal */
+    if ((chl->order  == AV_CHANNEL_ORDER_UNSPEC) !=
+        (chl1->order == AV_CHANNEL_ORDER_UNSPEC))
+        return 1;
+    /* both are unspecified -> equal */
+    else if (chl->order == AV_CHANNEL_ORDER_UNSPEC)
+        return 0;
+
+    /* can compare masks directly */
+    if (chl->order != AV_CHANNEL_ORDER_CUSTOM &&
+        chl->order == chl1->order)
+        return chl->u.mask != chl1->u.mask;
+
+    /* compare channel by channel */
+    for (i = 0; i < chl->nb_channels; i++)
+        if (av_channel_layout_channel_from_index(chl,  i) !=
+            av_channel_layout_channel_from_index(chl1, i))
+            return 1;
+    return 0;
+}
+
+void av_channel_layout_default(AVChannelLayout *ch_layout, int nb_channels)
+{
+    int i;
+    for (i = 0; i < FF_ARRAY_ELEMS(channel_layout_map); i++)
+        if (nb_channels == channel_layout_map[i].layout.nb_channels) {
+            *ch_layout = channel_layout_map[i].layout;
+            return;
+        }
+
+    ch_layout->order       = AV_CHANNEL_ORDER_UNSPEC;
+    ch_layout->nb_channels = nb_channels;
+}
+
+const AVChannelLayout *av_channel_layout_standard(void **opaque)
+{
+    uintptr_t i = (uintptr_t)*opaque;
+    const AVChannelLayout *ch_layout = NULL;
+
+    if (i < FF_ARRAY_ELEMS(channel_layout_map)) {
+        ch_layout = &channel_layout_map[i].layout;
+        *opaque = (void*)(i + 1);
+    }
+
+    return ch_layout;
+}
+
+uint64_t av_channel_layout_subset(const AVChannelLayout *channel_layout,
+                                  uint64_t mask)
+{
+    uint64_t ret = 0;
+    int i;
+
+    if (channel_layout->order == AV_CHANNEL_ORDER_NATIVE)
+        return channel_layout->u.mask & mask;
+
+    for (i = 0; i < 64; i++)
+        if (mask & (1ULL << i) && av_channel_layout_index_from_channel(channel_layout, i) >= 0)
+            ret |= (1ULL << i);
+
+    return ret;
+}
diff --git a/libavutil/channel_layout.h b/libavutil/channel_layout.h
index d39ae1177a..b1456c245e 100644
--- a/libavutil/channel_layout.h
+++ b/libavutil/channel_layout.h
@@ -23,6 +23,10 @@
 #define AVUTIL_CHANNEL_LAYOUT_H
 
 #include <stdint.h>
+#include <stdlib.h>
+
+#include "version.h"
+#include "attributes.h"
 
 /**
  * @file
@@ -34,6 +38,71 @@
  * @{
  */
 
+enum AVChannel {
+    ///< Invalid channel index
+    AV_CHAN_NONE = -1,
+    AV_CHAN_FRONT_LEFT,
+    AV_CHAN_FRONT_RIGHT,
+    AV_CHAN_FRONT_CENTER,
+    AV_CHAN_LOW_FREQUENCY,
+    AV_CHAN_BACK_LEFT,
+    AV_CHAN_BACK_RIGHT,
+    AV_CHAN_FRONT_LEFT_OF_CENTER,
+    AV_CHAN_FRONT_RIGHT_OF_CENTER,
+    AV_CHAN_BACK_CENTER,
+    AV_CHAN_SIDE_LEFT,
+    AV_CHAN_SIDE_RIGHT,
+    AV_CHAN_TOP_CENTER,
+    AV_CHAN_TOP_FRONT_LEFT,
+    AV_CHAN_TOP_FRONT_CENTER,
+    AV_CHAN_TOP_FRONT_RIGHT,
+    AV_CHAN_TOP_BACK_LEFT,
+    AV_CHAN_TOP_BACK_CENTER,
+    AV_CHAN_TOP_BACK_RIGHT,
+    /** Stereo downmix. */
+    AV_CHAN_STEREO_LEFT = 29,
+    /** See above. */
+    AV_CHAN_STEREO_RIGHT,
+    AV_CHAN_WIDE_LEFT,
+    AV_CHAN_WIDE_RIGHT,
+    AV_CHAN_SURROUND_DIRECT_LEFT,
+    AV_CHAN_SURROUND_DIRECT_RIGHT,
+    AV_CHAN_LOW_FREQUENCY_2,
+    AV_CHAN_TOP_SIDE_LEFT,
+    AV_CHAN_TOP_SIDE_RIGHT,
+    AV_CHAN_BOTTOM_FRONT_CENTER,
+    AV_CHAN_BOTTOM_FRONT_LEFT,
+    AV_CHAN_BOTTOM_FRONT_RIGHT,
+
+    /** Channel is empty can be safely skipped. */
+    AV_CHAN_UNUSED = 0x200,
+
+    /** Channel contains data, but its position is unknown. */
+    AV_CHAN_UNKNOWN = 0x300,
+};
+
+enum AVChannelOrder {
+    /**
+     * Only the channel count is specified, without any further information
+     * about the channel order.
+     */
+    AV_CHANNEL_ORDER_UNSPEC,
+    /**
+     * The native channel order, i.e. the channels are in the same order in
+     * which they are defined in the AVChannel enum. This supports up to 63
+     * different channels.
+     */
+    AV_CHANNEL_ORDER_NATIVE,
+    /**
+     * The channel order does not correspond to any other predefined order and
+     * is stored as an explicit map. For example, this could be used to support
+     * layouts with 64 or more channels, or with empty/skipped (AV_CHAN_SILENCE)
+     * channels at arbitrary positions.
+     */
+    AV_CHANNEL_ORDER_CUSTOM,
+};
+
+
 /**
  * @defgroup channel_masks Audio channel masks
  *
@@ -46,41 +115,46 @@
  *
  * @{
  */
-#define AV_CH_FRONT_LEFT             0x00000001
-#define AV_CH_FRONT_RIGHT            0x00000002
-#define AV_CH_FRONT_CENTER           0x00000004
-#define AV_CH_LOW_FREQUENCY          0x00000008
-#define AV_CH_BACK_LEFT              0x00000010
-#define AV_CH_BACK_RIGHT             0x00000020
-#define AV_CH_FRONT_LEFT_OF_CENTER   0x00000040
-#define AV_CH_FRONT_RIGHT_OF_CENTER  0x00000080
-#define AV_CH_BACK_CENTER            0x00000100
-#define AV_CH_SIDE_LEFT              0x00000200
-#define AV_CH_SIDE_RIGHT             0x00000400
-#define AV_CH_TOP_CENTER             0x00000800
-#define AV_CH_TOP_FRONT_LEFT         0x00001000
-#define AV_CH_TOP_FRONT_CENTER       0x00002000
-#define AV_CH_TOP_FRONT_RIGHT        0x00004000
-#define AV_CH_TOP_BACK_LEFT          0x00008000
-#define AV_CH_TOP_BACK_CENTER        0x00010000
-#define AV_CH_TOP_BACK_RIGHT         0x00020000
-#define AV_CH_STEREO_LEFT            0x20000000  ///< Stereo downmix.
-#define AV_CH_STEREO_RIGHT           0x40000000  ///< See AV_CH_STEREO_LEFT.
-#define AV_CH_WIDE_LEFT              0x0000000080000000ULL
-#define AV_CH_WIDE_RIGHT             0x0000000100000000ULL
-#define AV_CH_SURROUND_DIRECT_LEFT   0x0000000200000000ULL
-#define AV_CH_SURROUND_DIRECT_RIGHT  0x0000000400000000ULL
-#define AV_CH_LOW_FREQUENCY_2        0x0000000800000000ULL
-#define AV_CH_TOP_SIDE_LEFT          0x0000001000000000ULL
-#define AV_CH_TOP_SIDE_RIGHT         0x0000002000000000ULL
-#define AV_CH_BOTTOM_FRONT_CENTER    0x0000004000000000ULL
-#define AV_CH_BOTTOM_FRONT_LEFT      0x0000008000000000ULL
-#define AV_CH_BOTTOM_FRONT_RIGHT     0x0000010000000000ULL
+#define AV_CH_FRONT_LEFT             (1ULL << AV_CHAN_FRONT_LEFT           )
+#define AV_CH_FRONT_RIGHT            (1ULL << AV_CHAN_FRONT_RIGHT          )
+#define AV_CH_FRONT_CENTER           (1ULL << AV_CHAN_FRONT_CENTER         )
+#define AV_CH_LOW_FREQUENCY          (1ULL << AV_CHAN_LOW_FREQUENCY        )
+#define AV_CH_BACK_LEFT              (1ULL << AV_CHAN_BACK_LEFT            )
+#define AV_CH_BACK_RIGHT             (1ULL << AV_CHAN_BACK_RIGHT           )
+#define AV_CH_FRONT_LEFT_OF_CENTER   (1ULL << AV_CHAN_FRONT_LEFT_OF_CENTER )
+#define AV_CH_FRONT_RIGHT_OF_CENTER  (1ULL << AV_CHAN_FRONT_RIGHT_OF_CENTER)
+#define AV_CH_BACK_CENTER            (1ULL << AV_CHAN_BACK_CENTER          )
+#define AV_CH_SIDE_LEFT              (1ULL << AV_CHAN_SIDE_LEFT            )
+#define AV_CH_SIDE_RIGHT             (1ULL << AV_CHAN_SIDE_RIGHT           )
+#define AV_CH_TOP_CENTER             (1ULL << AV_CHAN_TOP_CENTER           )
+#define AV_CH_TOP_FRONT_LEFT         (1ULL << AV_CHAN_TOP_FRONT_LEFT       )
+#define AV_CH_TOP_FRONT_CENTER       (1ULL << AV_CHAN_TOP_FRONT_CENTER     )
+#define AV_CH_TOP_FRONT_RIGHT        (1ULL << AV_CHAN_TOP_FRONT_RIGHT      )
+#define AV_CH_TOP_BACK_LEFT          (1ULL << AV_CHAN_TOP_BACK_LEFT        )
+#define AV_CH_TOP_BACK_CENTER        (1ULL << AV_CHAN_TOP_BACK_CENTER      )
+#define AV_CH_TOP_BACK_RIGHT         (1ULL << AV_CHAN_TOP_BACK_RIGHT       )
+#define AV_CH_STEREO_LEFT            (1ULL << AV_CHAN_STEREO_LEFT          )
+#define AV_CH_STEREO_RIGHT           (1ULL << AV_CHAN_STEREO_RIGHT         )
+#define AV_CH_WIDE_LEFT              (1ULL << AV_CHAN_WIDE_LEFT            )
+#define AV_CH_WIDE_RIGHT             (1ULL << AV_CHAN_WIDE_RIGHT           )
+#define AV_CH_SURROUND_DIRECT_LEFT   (1ULL << AV_CHAN_SURROUND_DIRECT_LEFT )
+#define AV_CH_SURROUND_DIRECT_RIGHT  (1ULL << AV_CHAN_SURROUND_DIRECT_RIGHT)
+#define AV_CH_LOW_FREQUENCY_2        (1ULL << AV_CHAN_LOW_FREQUENCY_2      )
+#define AV_CH_TOP_SIDE_LEFT          (1ULL << AV_CHAN_TOP_SIDE_LEFT        )
+#define AV_CH_TOP_SIDE_RIGHT         (1ULL << AV_CHAN_TOP_SIDE_RIGHT       )
+#define AV_CH_BOTTOM_FRONT_CENTER    (1ULL << AV_CHAN_BOTTOM_FRONT_CENTER  )
+#define AV_CH_BOTTOM_FRONT_LEFT      (1ULL << AV_CHAN_BOTTOM_FRONT_LEFT    )
+#define AV_CH_BOTTOM_FRONT_RIGHT     (1ULL << AV_CHAN_BOTTOM_FRONT_RIGHT   )
 
+#if FF_API_OLD_CHANNEL_LAYOUT
 /** Channel mask value used for AVCodecContext.request_channel_layout
     to indicate that the user requests the channel order of the decoder output
-    to be the native codec channel order. */
+    to be the native codec channel order.
+    @deprecated channel order is now indicated in a special field in
+                AVChannelLayout
+    */
 #define AV_CH_LAYOUT_NATIVE          0x8000000000000000ULL
+#endif
 
 /**
  * @}
@@ -129,6 +203,141 @@ enum AVMatrixEncoding {
 };
 
 /**
+ * @}
+ */
+
+/**
+ * An AVChannelCustom defines a single channel within a custom order layout
+ *
+ * Unlike most structures in FFmpeg, sizeof(AVChannelCustom) is a part of the
+ * public ABI.
+ *
+ * No new fields may be added to it without a major version bump.
+ */
+typedef struct AVChannelCustom {
+    enum AVChannel id;
+    char name[16];
+    void *opaque;
+} AVChannelCustom;
+
+/**
+ * An AVChannelLayout holds information about the channel layout of audio data.
+ *
+ * A channel layout here is defined as a set of channels ordered in a specific
+ * way (unless the channel order is AV_CHANNEL_ORDER_UNSPEC, in which case an
+ * AVChannelLayout carries only the channel count).
+ *
+ * Unlike most structures in Libav, sizeof(AVChannelLayout) is a part of the
+ * public ABI and may be used by the caller. E.g. it may be allocated on stack
+ * or embedded in caller-defined structs.
+ *
+ * AVChannelLayout can be initialized as follows:
+ * - default initialization with {0}, followed by setting all used fields
+ *   correctly;
+ * - by assigning one of the predefined AV_CHANNEL_LAYOUT_* initializers;
+ * - with a constructor function, such as av_channel_layout_default(),
+ *   av_channel_layout_from_mask() or av_channel_layout_from_string().
+ *
+ * The channel layout must be unitialized with av_channel_layout_uninit()
+ *
+ * Copying an AVChannelLayout via assigning is forbidden,
+ * av_channel_layout_copy() must be used instead (and its return value should
+ * be checked)
+ *
+ * No new fields may be added to it without a major version bump, except for
+ * new elements of the union fitting in sizeof(uint64_t).
+ */
+typedef struct AVChannelLayout {
+    /**
+     * Channel order used in this layout.
+     * This is a mandatory field.
+     */
+    enum AVChannelOrder order;
+
+    /**
+     * Number of channels in this layout. Mandatory field.
+     */
+    int nb_channels;
+
+    /**
+     * Details about which channels are present in this layout.
+     * For AV_CHANNEL_ORDER_UNSPEC, this field is undefined and must not be
+     * used.
+     */
+    union {
+        /**
+         * This member must be used for AV_CHANNEL_ORDER_NATIVE.
+         * It is a bitmask, where the position of each set bit means that the
+         * AVChannel with the corresponding value is present.
+         *
+         * I.e. when (mask & (1 << AV_CHAN_FOO)) is non-zero, then AV_CHAN_FOO
+         * is present in the layout. Otherwise it is not present.
+         *
+         * @note when a channel layout using a bitmask is constructed or
+         * modified manually (i.e.  not using any of the av_channel_layout_*
+         * functions), the code doing it must ensure that the number of set bits
+         * is equal to nb_channels.
+         */
+        uint64_t mask;
+        /**
+         * This member must be used when the channel order is
+         * AV_CHANNEL_ORDER_CUSTOM. It is a nb_channels-sized array, with each
+         * element signalling the presence of the AVChannel with the
+         * corresponding value in map[i].id.
+         *
+         * I.e. when map[i].id is equal to AV_CHAN_FOO, then AV_CH_FOO is the
+         * i-th channel in the audio data.
+         *
+         * map[i].name may be filled with a 0-terminated string, in which case
+         * it will be used for the purpose of identifying the channel with the
+         * convenience functions below. Otherise it must be zeroed.
+         */
+        AVChannelCustom *map;
+    } u;
+
+    /**
+     * For some private data of the user.
+     */
+    void *opaque;
+} AVChannelLayout;
+
+#define AV_CHANNEL_LAYOUT_MASK(nb, m) \
+    { .order = AV_CHANNEL_ORDER_NATIVE, .nb_channels = (nb), .u = { .mask = (m) }}
+
+#define AV_CHANNEL_LAYOUT_MONO              AV_CHANNEL_LAYOUT_MASK(1,  AV_CH_LAYOUT_MONO)
+#define AV_CHANNEL_LAYOUT_STEREO            AV_CHANNEL_LAYOUT_MASK(2,  AV_CH_LAYOUT_STEREO)
+#define AV_CHANNEL_LAYOUT_2POINT1           AV_CHANNEL_LAYOUT_MASK(3,  AV_CH_LAYOUT_2POINT1)
+#define AV_CHANNEL_LAYOUT_2_1               AV_CHANNEL_LAYOUT_MASK(3,  AV_CH_LAYOUT_2_1)
+#define AV_CHANNEL_LAYOUT_SURROUND          AV_CHANNEL_LAYOUT_MASK(3,  AV_CH_LAYOUT_SURROUND)
+#define AV_CHANNEL_LAYOUT_3POINT1           AV_CHANNEL_LAYOUT_MASK(4,  AV_CH_LAYOUT_3POINT1)
+#define AV_CHANNEL_LAYOUT_4POINT0           AV_CHANNEL_LAYOUT_MASK(4,  AV_CH_LAYOUT_4POINT0)
+#define AV_CHANNEL_LAYOUT_4POINT1           AV_CHANNEL_LAYOUT_MASK(5,  AV_CH_LAYOUT_4POINT1)
+#define AV_CHANNEL_LAYOUT_2_2               AV_CHANNEL_LAYOUT_MASK(4,  AV_CH_LAYOUT_2_2)
+#define AV_CHANNEL_LAYOUT_QUAD              AV_CHANNEL_LAYOUT_MASK(4,  AV_CH_LAYOUT_QUAD)
+#define AV_CHANNEL_LAYOUT_5POINT0           AV_CHANNEL_LAYOUT_MASK(5,  AV_CH_LAYOUT_5POINT0)
+#define AV_CHANNEL_LAYOUT_5POINT1           AV_CHANNEL_LAYOUT_MASK(6,  AV_CH_LAYOUT_5POINT1)
+#define AV_CHANNEL_LAYOUT_5POINT0_BACK      AV_CHANNEL_LAYOUT_MASK(5,  AV_CH_LAYOUT_5POINT0_BACK)
+#define AV_CHANNEL_LAYOUT_5POINT1_BACK      AV_CHANNEL_LAYOUT_MASK(6,  AV_CH_LAYOUT_5POINT1_BACK)
+#define AV_CHANNEL_LAYOUT_6POINT0           AV_CHANNEL_LAYOUT_MASK(6,  AV_CH_LAYOUT_6POINT0)
+#define AV_CHANNEL_LAYOUT_6POINT0_FRONT     AV_CHANNEL_LAYOUT_MASK(6,  AV_CH_LAYOUT_6POINT0_FRONT)
+#define AV_CHANNEL_LAYOUT_HEXAGONAL         AV_CHANNEL_LAYOUT_MASK(6,  AV_CH_LAYOUT_HEXAGONAL)
+#define AV_CHANNEL_LAYOUT_6POINT1           AV_CHANNEL_LAYOUT_MASK(7,  AV_CH_LAYOUT_6POINT1)
+#define AV_CHANNEL_LAYOUT_6POINT1_BACK      AV_CHANNEL_LAYOUT_MASK(7,  AV_CH_LAYOUT_6POINT1_BACK)
+#define AV_CHANNEL_LAYOUT_6POINT1_FRONT     AV_CHANNEL_LAYOUT_MASK(7,  AV_CH_LAYOUT_6POINT1_FRONT)
+#define AV_CHANNEL_LAYOUT_7POINT0           AV_CHANNEL_LAYOUT_MASK(7,  AV_CH_LAYOUT_7POINT0)
+#define AV_CHANNEL_LAYOUT_7POINT0_FRONT     AV_CHANNEL_LAYOUT_MASK(7,  AV_CH_LAYOUT_7POINT0_FRONT)
+#define AV_CHANNEL_LAYOUT_7POINT1           AV_CHANNEL_LAYOUT_MASK(8,  AV_CH_LAYOUT_7POINT1)
+#define AV_CHANNEL_LAYOUT_7POINT1_WIDE      AV_CHANNEL_LAYOUT_MASK(8,  AV_CH_LAYOUT_7POINT1_WIDE)
+#define AV_CHANNEL_LAYOUT_7POINT1_WIDE_BACK AV_CHANNEL_LAYOUT_MASK(8,  AV_CH_LAYOUT_7POINT1_WIDE_BACK)
+#define AV_CHANNEL_LAYOUT_OCTAGONAL         AV_CHANNEL_LAYOUT_MASK(8,  AV_CH_LAYOUT_OCTAGONAL)
+#define AV_CHANNEL_LAYOUT_HEXADECAGONAL     AV_CHANNEL_LAYOUT_MASK(16, AV_CH_LAYOUT_HEXADECAGONAL)
+#define AV_CHANNEL_LAYOUT_STEREO_DOWNMIX    AV_CHANNEL_LAYOUT_MASK(2,  AV_CH_LAYOUT_STEREO_DOWNMIX)
+#define AV_CHANNEL_LAYOUT_22POINT2          AV_CHANNEL_LAYOUT_MASK(24, AV_CH_LAYOUT_22POINT2)
+
+struct AVBPrint;
+
+#if FF_API_OLD_CHANNEL_LAYOUT
+/**
  * Return a channel layout id that matches name, or 0 if no match is found.
  *
  * name can be one or several of the following notations,
@@ -144,7 +353,10 @@ enum AVMatrixEncoding {
  *   AV_CH_* macros).
  *
  * Example: "stereo+FC" = "2c+FC" = "2c+1c" = "0x7"
+ *
+ * @deprecated use av_channel_layout_from_string()
  */
+attribute_deprecated
 uint64_t av_get_channel_layout(const char *name);
 
 /**
@@ -158,7 +370,9 @@ uint64_t av_get_channel_layout(const char *name);
  * @param[out] nb_channels      number of channels
  *
  * @return 0 on success, AVERROR(EINVAL) if the parsing fails.
+ * @deprecated use av_channel_layout_from_string()
  */
+attribute_deprecated
 int av_get_extended_channel_layout(const char *name, uint64_t* channel_layout, int* nb_channels);
 
 /**
@@ -167,23 +381,31 @@ int av_get_extended_channel_layout(const char *name, uint64_t* channel_layout, i
  *
  * @param buf put here the string containing the channel layout
  * @param buf_size size in bytes of the buffer
+ * @deprecated use av_channel_layout_describe()
  */
+attribute_deprecated
 void av_get_channel_layout_string(char *buf, int buf_size, int nb_channels, uint64_t channel_layout);
 
-struct AVBPrint;
 /**
  * Append a description of a channel layout to a bprint buffer.
+ * @deprecated use av_channel_layout_describe()
  */
+attribute_deprecated
 void av_bprint_channel_layout(struct AVBPrint *bp, int nb_channels, uint64_t channel_layout);
 
 /**
  * Return the number of channels in the channel layout.
+ * @deprecated use AVChannelLayout.nb_channels
  */
+attribute_deprecated
 int av_get_channel_layout_nb_channels(uint64_t channel_layout);
 
 /**
  * Return default channel layout for a given number of channels.
+ *
+ * @deprecated use av_channel_layout_default()
  */
+attribute_deprecated
 int64_t av_get_default_channel_layout(int nb_channels);
 
 /**
@@ -194,20 +416,28 @@ int64_t av_get_default_channel_layout(int nb_channels);
  *
  * @return index of channel in channel_layout on success, a negative AVERROR
  *         on error.
+ *
+ * @deprecated use av_channel_layout_index_from_channel()
  */
+attribute_deprecated
 int av_get_channel_layout_channel_index(uint64_t channel_layout,
                                         uint64_t channel);
 
 /**
  * Get the channel with the given index in channel_layout.
+ * @deprecated use av_channel_layout_channel_from_index()
  */
+attribute_deprecated
 uint64_t av_channel_layout_extract_channel(uint64_t channel_layout, int index);
 
 /**
  * Get the name of a given channel.
  *
  * @return channel name on success, NULL on error.
+ *
+ * @deprecated use av_channel_name()
  */
+attribute_deprecated
 const char *av_get_channel_name(uint64_t channel);
 
 /**
@@ -215,7 +445,9 @@ const char *av_get_channel_name(uint64_t channel);
  *
  * @param channel  a channel layout with a single channel
  * @return  channel description on success, NULL on error
+ * @deprecated use av_channel_description()
  */
+attribute_deprecated
 const char *av_get_channel_description(uint64_t channel);
 
 /**
@@ -226,9 +458,238 @@ const char *av_get_channel_description(uint64_t channel);
  * @param[out] name    name of the layout
  * @return  0  if the layout exists,
  *          <0 if index is beyond the limits
+ * @deprecated use av_channel_layout_standard()
  */
+attribute_deprecated
 int av_get_standard_channel_layout(unsigned index, uint64_t *layout,
                                    const char **name);
+#endif
+
+/**
+ * Get a human readable string in an abbreviated form describing a given channel.
+ * This is the inverse function of @ref av_channel_from_string().
+ *
+ * @param buf pre-allocated buffer where to put the generated string
+ * @param buf_size size in bytes of the buffer.
+ * @return amount of bytes needed to hold the output string, or a negative AVERROR
+ *         on failure. If the returned value is bigger than buf_size, then the
+ *         string was truncated.
+ */
+int av_channel_name(char *buf, size_t buf_size, enum AVChannel channel);
+
+/**
+ * bprint variant of av_channel_name().
+ *
+ * @note the string will be appended to the bprint buffer.
+ */
+void av_channel_name_bprint(struct AVBPrint *bp, enum AVChannel channel_id);
+
+/**
+ * Get a human readable string describing a given channel.
+ *
+ * @param buf pre-allocated buffer where to put the generated string
+ * @param buf_size size in bytes of the buffer.
+ * @return amount of bytes needed to hold the output string, or a negative AVERROR
+ *         on failure. If the returned value is bigger than buf_size, then the
+ *         string was truncated.
+ */
+int av_channel_description(char *buf, size_t buf_size, enum AVChannel channel);
+
+/**
+ * bprint variant of av_channel_description().
+ *
+ * @note the string will be appended to the bprint buffer.
+ */
+void av_channel_description_bprint(struct AVBPrint *bp, enum AVChannel channel_id);
+
+/**
+ * This is the inverse function of @ref av_channel_name().
+ *
+ * @return the channel with the given name
+ *         AV_CHAN_NONE when name does not identify a known channel
+ */
+enum AVChannel av_channel_from_string(const char *name);
+
+/**
+ * Initialize a native channel layout from a bitmask indicating which channels
+ * are present.
+ *
+ * @param channel_layout the layout structure to be initialized
+ * @param mask bitmask describing the channel layout
+ *
+ * @return 0 on success
+ *         AVERROR(EINVAL) for invalid mask values
+ */
+int av_channel_layout_from_mask(AVChannelLayout *channel_layout, uint64_t mask);
+
+/**
+ * Initialize a channel layout from a given string description.
+ * The input string can be represented by:
+ *  - the formal channel layout name (returned by av_channel_layout_describe())
+ *  - single or multiple channel names (returned by av_channel_name(), eg. "FL",
+ *    or concatenated with "+", each optionally containing a custom name after
+ *    a "@", eg. "FL@Left+FR@Right+LFE")
+ *  - a decimal or hexadecimal value of a native channel layout (eg. "4" or "0x4")
+ *  - the number of channels with default layout (eg. "4c")
+ *  - the number of unordered channels (eg. "4C" or "4 channels")
+ *
+ * @param channel_layout input channel layout
+ * @param str string describing the channel layout
+ * @return 0 channel layout was detected, AVERROR_INVALIDATATA otherwise
+ */
+int av_channel_layout_from_string(AVChannelLayout *channel_layout,
+                                  const char *str);
+
+/**
+ * Get the default channel layout for a given number of channels.
+ *
+ * @param channel_layout the layout structure to be initialized
+ * @param nb_channels number of channels
+ */
+void av_channel_layout_default(AVChannelLayout *ch_layout, int nb_channels);
+
+/**
+ * Iterate over all standard channel layouts.
+ *
+ * @param opaque a pointer where libavutil will store the iteration state. Must
+ *               point to NULL to start the iteration.
+ *
+ * @return the standard channel layout or NULL when the iteration is
+ *         finished
+ */
+const AVChannelLayout *av_channel_layout_standard(void **opaque);
+
+/**
+ * Free any allocated data in the channel layout and reset the channel
+ * count to 0.
+ *
+ * @param channel_layout the layout structure to be uninitialized
+ */
+void av_channel_layout_uninit(AVChannelLayout *channel_layout);
+
+/**
+ * Make a copy of a channel layout. This differs from just assigning src to dst
+ * in that it allocates and copies the map for AV_CHANNEL_ORDER_CUSTOM.
+ *
+ * @note the destination channel_layout will be always uninitialized before copy.
+ *
+ * @param dst destination channel layout
+ * @param src source channel layout
+ * @return 0 on success, a negative AVERROR on error.
+ */
+int av_channel_layout_copy(AVChannelLayout *dst, const AVChannelLayout *src);
+
+/**
+ * Get a human-readable string describing the channel layout properties.
+ * The string will be in the same format that is accepted by
+ * @ref av_channel_layout_from_string(), allowing to rebuild the same
+ * channel layout, except for opaque pointers.
+ *
+ * @param channel_layout channel layout to be described
+ * @param buf pre-allocated buffer where to put the generated string
+ * @param buf_size size in bytes of the buffer.
+ * @return amount of bytes needed to hold the output string, or a negative AVERROR
+ *         on failure. If the returned value is bigger than buf_size, then the
+ *         string was truncated.
+ */
+int av_channel_layout_describe(const AVChannelLayout *channel_layout,
+                               char *buf, size_t buf_size);
+
+/**
+ * bprint variant of av_channel_layout_describe().
+ *
+ * @note the string will be appended to the bprint buffer.
+ * @return 0 on success, or a negative AVERROR value on failure.
+ */
+int av_channel_layout_describe_bprint(const AVChannelLayout *channel_layout,
+                                      struct AVBPrint *bp);
+
+/**
+ * Get the channel with the given index in a channel layout.
+ *
+ * @param channel_layout input channel layout
+ * @return channel with the index idx in channel_layout on success or
+ *         AV_CHAN_NONE on failure (if idx is not valid or the channel order is
+ *         unspecified)
+ */
+enum AVChannel
+av_channel_layout_channel_from_index(const AVChannelLayout *channel_layout, unsigned int idx);
+
+/**
+ * Get the index of a given channel in a channel layout. In case multiple
+ * channels are found, only the first match will be returned.
+ *
+ * @param channel_layout input channel layout
+ * @return index of channel in channel_layout on success or a negative number if
+ *         channel is not present in channel_layout.
+ */
+int av_channel_layout_index_from_channel(const AVChannelLayout *channel_layout,
+                                         enum AVChannel channel);
+
+/**
+ * Get the index in a channel layout of a channel described by the given string.
+ * In case multiple channels are found, only the first match will be returned.
+ *
+ * This function accepts channel names in the same format as
+ * @ref av_channel_from_string().
+ *
+ * @param channel_layout input channel layout
+ * @return a channel index described by the given string, or a negative AVERROR
+ *         value.
+ */
+int av_channel_layout_index_from_string(const AVChannelLayout *channel_layout,
+                                        const char *name);
+
+/**
+ * Get a channel described by the given string.
+ *
+ * This function accepts channel names in the same format as
+ * @ref av_channel_from_string().
+ *
+ * @param channel_layout input channel layout
+ * @return a channel described by the given string in channel_layout on success
+ *         or AV_CHAN_NONE on failure (if the string is not valid or the channel
+ *         order is unspecified)
+ */
+enum AVChannel
+av_channel_layout_channel_from_string(const AVChannelLayout *channel_layout,
+                                      const char *name);
+
+/**
+ * Find out what channels from a given set are present in a channel layout,
+ * without regard for their positions.
+ *
+ * @param channel_layout input channel layout
+ * @param mask a combination of AV_CH_* representing a set of channels
+ * @return a bitfield representing all the channels from mask that are present
+ *         in channel_layout
+ */
+uint64_t av_channel_layout_subset(const AVChannelLayout *channel_layout,
+                                  uint64_t mask);
+
+/**
+ * Check whether a channel layout is valid, i.e. can possibly describe audio
+ * data.
+ *
+ * @param channel_layout input channel layout
+ * @return 1 if channel_layout is valid, 0 otherwise.
+ */
+int av_channel_layout_check(const AVChannelLayout *channel_layout);
+
+/**
+ * Check whether two channel layouts are semantically the same, i.e. the same
+ * channels are present on the same positions in both.
+ *
+ * If one of the channel layouts is AV_CHANNEL_ORDER_UNSPEC, while the other is
+ * not, they are considered to be unequal. If both are AV_CHANNEL_ORDER_UNSPEC,
+ * they are considered equal iff the channel counts are the same in both.
+ *
+ * @param chl input channel layout
+ * @param chl1 input channel layout
+ * @return 0 if chl and chl1 are equal, 1 if they are not equal. A negative
+ *         AVERROR code if one or both are invalid.
+ */
+int av_channel_layout_compare(const AVChannelLayout *chl, const AVChannelLayout *chl1);
 
 /**
  * @}
diff --git a/libavutil/version.h b/libavutil/version.h
index 6c5d90507c..f52913753d 100644
--- a/libavutil/version.h
+++ b/libavutil/version.h
@@ -112,6 +112,7 @@
 #define FF_API_FIFO_PEEK2               (LIBAVUTIL_VERSION_MAJOR < 58)
 #define FF_API_FIFO_OLD_API             (LIBAVUTIL_VERSION_MAJOR < 58)
 #define FF_API_XVMC                     (LIBAVUTIL_VERSION_MAJOR < 58)
+#define FF_API_OLD_CHANNEL_LAYOUT       (LIBAVUTIL_VERSION_MAJOR < 58)
 
 /**
  * @}