avcodec/opus: Move stuff shared by decoder and parser to a new file

opus.h (which is used by all the Opus code) currently includes
several structures only used by the parser and the decoder;
several elements of OpusContext are even only used by the decoder.

This commit therefore moves the part of OpusContext that is shared
between these two components (and used by ff_opus_parse_extradata())
out into a new structure and moves all the other accompanying
structures and functions to a new header, opus_parse.h; the
functions itself are also moved to a new file, opus_parse.c.
(This also allows to remove several spurious dependencies
of the Opus parser and encoder.)

Reviewed-by: Lynne <dev@lynne.ee>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

1 files changed, 469 insertions, 0 deletions

diff --git a/libavcodec/opus_parse.c b/libavcodec/opus_parse.c
new file mode 100644
index 0000000000..39765c5b79
--- /dev/null
+++ b/libavcodec/opus_parse.c
@@ -0,0 +1,469 @@
+/*
+ * Copyright (c) 2012 Andrew D'Addesio
+ * Copyright (c) 2013-2014 Mozilla Corporation
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * Opus decoder/parser shared code
+ */
+
+#include "libavutil/attributes.h"
+#include "libavutil/channel_layout.h"
+#include "libavutil/error.h"
+#include "libavutil/intreadwrite.h"
+#include "libavutil/log.h"
+#include "libavutil/mem.h"
+
+#include "avcodec.h"
+#include "internal.h"
+#include "mathops.h"
+#include "opus.h"
+#include "opus_parse.h"
+#include "vorbis_data.h"
+
+static const uint16_t opus_frame_duration[32] = {
+    480, 960, 1920, 2880,
+    480, 960, 1920, 2880,
+    480, 960, 1920, 2880,
+    480, 960,
+    480, 960,
+    120, 240,  480,  960,
+    120, 240,  480,  960,
+    120, 240,  480,  960,
+    120, 240,  480,  960,
+};
+
+/**
+ * Read a 1- or 2-byte frame length
+ */
+static inline int xiph_lacing_16bit(const uint8_t **ptr, const uint8_t *end)
+{
+    int val;
+
+    if (*ptr >= end)
+        return AVERROR_INVALIDDATA;
+    val = *(*ptr)++;
+    if (val >= 252) {
+        if (*ptr >= end)
+            return AVERROR_INVALIDDATA;
+        val += 4 * *(*ptr)++;
+    }
+    return val;
+}
+
+/**
+ * Read a multi-byte length (used for code 3 packet padding size)
+ */
+static inline int xiph_lacing_full(const uint8_t **ptr, const uint8_t *end)
+{
+    int val = 0;
+    int next;
+
+    while (1) {
+        if (*ptr >= end || val > INT_MAX - 254)
+            return AVERROR_INVALIDDATA;
+        next = *(*ptr)++;
+        val += next;
+        if (next < 255)
+            break;
+        else
+            val--;
+    }
+    return val;
+}
+
+/**
+ * Parse Opus packet info from raw packet data
+ */
+int ff_opus_parse_packet(OpusPacket *pkt, const uint8_t *buf, int buf_size,
+                         int self_delimiting)
+{
+    const uint8_t *ptr = buf;
+    const uint8_t *end = buf + buf_size;
+    int padding = 0;
+    int frame_bytes, i;
+
+    if (buf_size < 1)
+        goto fail;
+
+    /* TOC byte */
+    i = *ptr++;
+    pkt->code   = (i     ) & 0x3;
+    pkt->stereo = (i >> 2) & 0x1;
+    pkt->config = (i >> 3) & 0x1F;
+
+    /* code 2 and code 3 packets have at least 1 byte after the TOC */
+    if (pkt->code >= 2 && buf_size < 2)
+        goto fail;
+
+    switch (pkt->code) {
+    case 0:
+        /* 1 frame */
+        pkt->frame_count = 1;
+        pkt->vbr         = 0;
+
+        if (self_delimiting) {
+            int len = xiph_lacing_16bit(&ptr, end);
+            if (len < 0 || len > end - ptr)
+                goto fail;
+            end      = ptr + len;
+            buf_size = end - buf;
+        }
+
+        frame_bytes = end - ptr;
+        if (frame_bytes > MAX_FRAME_SIZE)
+            goto fail;
+        pkt->frame_offset[0] = ptr - buf;
+        pkt->frame_size[0]   = frame_bytes;
+        break;
+    case 1:
+        /* 2 frames, equal size */
+        pkt->frame_count = 2;
+        pkt->vbr         = 0;
+
+        if (self_delimiting) {
+            int len = xiph_lacing_16bit(&ptr, end);
+            if (len < 0 || 2 * len > end - ptr)
+                goto fail;
+            end      = ptr + 2 * len;
+            buf_size = end - buf;
+        }
+
+        frame_bytes = end - ptr;
+        if (frame_bytes & 1 || frame_bytes >> 1 > MAX_FRAME_SIZE)
+            goto fail;
+        pkt->frame_offset[0] = ptr - buf;
+        pkt->frame_size[0]   = frame_bytes >> 1;
+        pkt->frame_offset[1] = pkt->frame_offset[0] + pkt->frame_size[0];
+        pkt->frame_size[1]   = frame_bytes >> 1;
+        break;
+    case 2:
+        /* 2 frames, different sizes */
+        pkt->frame_count = 2;
+        pkt->vbr         = 1;
+
+        /* read 1st frame size */
+        frame_bytes = xiph_lacing_16bit(&ptr, end);
+        if (frame_bytes < 0)
+            goto fail;
+
+        if (self_delimiting) {
+            int len = xiph_lacing_16bit(&ptr, end);
+            if (len < 0 || len + frame_bytes > end - ptr)
+                goto fail;
+            end      = ptr + frame_bytes + len;
+            buf_size = end - buf;
+        }
+
+        pkt->frame_offset[0] = ptr - buf;
+        pkt->frame_size[0]   = frame_bytes;
+
+        /* calculate 2nd frame size */
+        frame_bytes = end - ptr - pkt->frame_size[0];
+        if (frame_bytes < 0 || frame_bytes > MAX_FRAME_SIZE)
+            goto fail;
+        pkt->frame_offset[1] = pkt->frame_offset[0] + pkt->frame_size[0];
+        pkt->frame_size[1]   = frame_bytes;
+        break;
+    case 3:
+        /* 1 to 48 frames, can be different sizes */
+        i = *ptr++;
+        pkt->frame_count = (i     ) & 0x3F;
+        padding          = (i >> 6) & 0x01;
+        pkt->vbr         = (i >> 7) & 0x01;
+
+        if (pkt->frame_count == 0 || pkt->frame_count > MAX_FRAMES)
+            goto fail;
+
+        /* read padding size */
+        if (padding) {
+            padding = xiph_lacing_full(&ptr, end);
+            if (padding < 0)
+                goto fail;
+        }
+
+        /* read frame sizes */
+        if (pkt->vbr) {
+            /* for VBR, all frames except the final one have their size coded
+               in the bitstream. the last frame size is implicit. */
+            int total_bytes = 0;
+            for (i = 0; i < pkt->frame_count - 1; i++) {
+                frame_bytes = xiph_lacing_16bit(&ptr, end);
+                if (frame_bytes < 0)
+                    goto fail;
+                pkt->frame_size[i] = frame_bytes;
+                total_bytes += frame_bytes;
+            }
+
+            if (self_delimiting) {
+                int len = xiph_lacing_16bit(&ptr, end);
+                if (len < 0 || len + total_bytes + padding > end - ptr)
+                    goto fail;
+                end      = ptr + total_bytes + len + padding;
+                buf_size = end - buf;
+            }
+
+            frame_bytes = end - ptr - padding;
+            if (total_bytes > frame_bytes)
+                goto fail;
+            pkt->frame_offset[0] = ptr - buf;
+            for (i = 1; i < pkt->frame_count; i++)
+                pkt->frame_offset[i] = pkt->frame_offset[i-1] + pkt->frame_size[i-1];
+            pkt->frame_size[pkt->frame_count-1] = frame_bytes - total_bytes;
+        } else {
+            /* for CBR, the remaining packet bytes are divided evenly between
+               the frames */
+            if (self_delimiting) {
+                frame_bytes = xiph_lacing_16bit(&ptr, end);
+                if (frame_bytes < 0 || pkt->frame_count * frame_bytes + padding > end - ptr)
+                    goto fail;
+                end      = ptr + pkt->frame_count * frame_bytes + padding;
+                buf_size = end - buf;
+            } else {
+                frame_bytes = end - ptr - padding;
+                if (frame_bytes % pkt->frame_count ||
+                    frame_bytes / pkt->frame_count > MAX_FRAME_SIZE)
+                    goto fail;
+                frame_bytes /= pkt->frame_count;
+            }
+
+            pkt->frame_offset[0] = ptr - buf;
+            pkt->frame_size[0]   = frame_bytes;
+            for (i = 1; i < pkt->frame_count; i++) {
+                pkt->frame_offset[i] = pkt->frame_offset[i-1] + pkt->frame_size[i-1];
+                pkt->frame_size[i]   = frame_bytes;
+            }
+        }
+    }
+
+    pkt->packet_size = buf_size;
+    pkt->data_size   = pkt->packet_size - padding;
+
+    /* total packet duration cannot be larger than 120ms */
+    pkt->frame_duration = opus_frame_duration[pkt->config];
+    if (pkt->frame_duration * pkt->frame_count > MAX_PACKET_DUR)
+        goto fail;
+
+    /* set mode and bandwidth */
+    if (pkt->config < 12) {
+        pkt->mode = OPUS_MODE_SILK;
+        pkt->bandwidth = pkt->config >> 2;
+    } else if (pkt->config < 16) {
+        pkt->mode = OPUS_MODE_HYBRID;
+        pkt->bandwidth = OPUS_BANDWIDTH_SUPERWIDEBAND + (pkt->config >= 14);
+    } else {
+        pkt->mode = OPUS_MODE_CELT;
+        pkt->bandwidth = (pkt->config - 16) >> 2;
+        /* skip medium band */
+        if (pkt->bandwidth)
+            pkt->bandwidth++;
+    }
+
+    return 0;
+
+fail:
+    memset(pkt, 0, sizeof(*pkt));
+    return AVERROR_INVALIDDATA;
+}
+
+static int channel_reorder_vorbis(int nb_channels, int channel_idx)
+{
+    return ff_vorbis_channel_layout_offsets[nb_channels - 1][channel_idx];
+}
+
+static int channel_reorder_unknown(int nb_channels, int channel_idx)
+{
+    return channel_idx;
+}
+
+av_cold int ff_opus_parse_extradata(AVCodecContext *avctx,
+                                    OpusParseContext *s)
+{
+    static const uint8_t default_channel_map[2] = { 0, 1 };
+
+    int (*channel_reorder)(int, int) = channel_reorder_unknown;
+    int channels = avctx->ch_layout.nb_channels;
+
+    const uint8_t *extradata, *channel_map;
+    int extradata_size;
+    int version, map_type, streams, stereo_streams, i, j, ret;
+    AVChannelLayout layout = { 0 };
+
+    if (!avctx->extradata) {
+        if (channels > 2) {
+            av_log(avctx, AV_LOG_ERROR,
+                   "Multichannel configuration without extradata.\n");
+            return AVERROR(EINVAL);
+        }
+        extradata      = opus_default_extradata;
+        extradata_size = sizeof(opus_default_extradata);
+    } else {
+        extradata = avctx->extradata;
+        extradata_size = avctx->extradata_size;
+    }
+
+    if (extradata_size < 19) {
+        av_log(avctx, AV_LOG_ERROR, "Invalid extradata size: %d\n",
+               extradata_size);
+        return AVERROR_INVALIDDATA;
+    }
+
+    version = extradata[8];
+    if (version > 15) {
+        avpriv_request_sample(avctx, "Extradata version %d", version);
+        return AVERROR_PATCHWELCOME;
+    }
+
+    avctx->delay = AV_RL16(extradata + 10);
+    if (avctx->internal)
+        avctx->internal->skip_samples = avctx->delay;
+
+    channels = avctx->extradata ? extradata[9] : (channels == 1) ? 1 : 2;
+    if (!channels) {
+        av_log(avctx, AV_LOG_ERROR, "Zero channel count specified in the extradata\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    s->gain_i = AV_RL16(extradata + 16);
+
+    map_type = extradata[18];
+    if (!map_type) {
+        if (channels > 2) {
+            av_log(avctx, AV_LOG_ERROR,
+                   "Channel mapping 0 is only specified for up to 2 channels\n");
+            ret = AVERROR_INVALIDDATA;
+            goto fail;
+        }
+        layout         = (channels == 1) ? (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO :
+                                           (AVChannelLayout)AV_CHANNEL_LAYOUT_STEREO;
+        streams        = 1;
+        stereo_streams = channels - 1;
+        channel_map    = default_channel_map;
+    } else if (map_type == 1 || map_type == 2 || map_type == 255) {
+        if (extradata_size < 21 + channels) {
+            av_log(avctx, AV_LOG_ERROR, "Invalid extradata size: %d\n",
+                   extradata_size);
+            ret = AVERROR_INVALIDDATA;
+            goto fail;
+        }
+
+        streams        = extradata[19];
+        stereo_streams = extradata[20];
+        if (!streams || stereo_streams > streams ||
+            streams + stereo_streams > 255) {
+            av_log(avctx, AV_LOG_ERROR,
+                   "Invalid stream/stereo stream count: %d/%d\n", streams, stereo_streams);
+            ret = AVERROR_INVALIDDATA;
+            goto fail;
+        }
+
+        if (map_type == 1) {
+            if (channels > 8) {
+                av_log(avctx, AV_LOG_ERROR,
+                       "Channel mapping 1 is only specified for up to 8 channels\n");
+                ret = AVERROR_INVALIDDATA;
+                goto fail;
+            }
+            av_channel_layout_copy(&layout, &ff_vorbis_ch_layouts[channels - 1]);
+            channel_reorder = channel_reorder_vorbis;
+        } else if (map_type == 2) {
+            int ambisonic_order = ff_sqrt(channels) - 1;
+            if (channels != ((ambisonic_order + 1) * (ambisonic_order + 1)) &&
+                channels != ((ambisonic_order + 1) * (ambisonic_order + 1) + 2)) {
+                av_log(avctx, AV_LOG_ERROR,
+                       "Channel mapping 2 is only specified for channel counts"
+                       " which can be written as (n + 1)^2 or (n + 1)^2 + 2"
+                       " for nonnegative integer n\n");
+                ret = AVERROR_INVALIDDATA;
+                goto fail;
+            }
+            if (channels > 227) {
+                av_log(avctx, AV_LOG_ERROR, "Too many channels\n");
+                ret = AVERROR_INVALIDDATA;
+                goto fail;
+            }
+
+            layout.order = AV_CHANNEL_ORDER_AMBISONIC;
+            layout.nb_channels = channels;
+            if (channels != ((ambisonic_order + 1) * (ambisonic_order + 1)))
+                layout.u.mask = AV_CH_LAYOUT_STEREO;
+        } else {
+            layout.order       = AV_CHANNEL_ORDER_UNSPEC;
+            layout.nb_channels = channels;
+        }
+
+        channel_map = extradata + 21;
+    } else {
+        avpriv_request_sample(avctx, "Mapping type %d", map_type);
+        return AVERROR_PATCHWELCOME;
+    }
+
+    s->channel_maps = av_calloc(channels, sizeof(*s->channel_maps));
+    if (!s->channel_maps) {
+        ret = AVERROR(ENOMEM);
+        goto fail;
+    }
+
+    for (i = 0; i < channels; i++) {
+        ChannelMap *map = &s->channel_maps[i];
+        uint8_t     idx = channel_map[channel_reorder(channels, i)];
+
+        if (idx == 255) {
+            map->silence = 1;
+            continue;
+        } else if (idx >= streams + stereo_streams) {
+            av_log(avctx, AV_LOG_ERROR,
+                   "Invalid channel map for output channel %d: %d\n", i, idx);
+            av_freep(&s->channel_maps);
+            ret = AVERROR_INVALIDDATA;
+            goto fail;
+        }
+
+        /* check that we did not see this index yet */
+        map->copy = 0;
+        for (j = 0; j < i; j++)
+            if (channel_map[channel_reorder(channels, j)] == idx) {
+                map->copy     = 1;
+                map->copy_idx = j;
+                break;
+            }
+
+        if (idx < 2 * stereo_streams) {
+            map->stream_idx  = idx / 2;
+            map->channel_idx = idx & 1;
+        } else {
+            map->stream_idx  = idx - stereo_streams;
+            map->channel_idx = 0;
+        }
+    }
+
+    ret = av_channel_layout_copy(&avctx->ch_layout, &layout);
+    if (ret < 0)
+        goto fail;
+
+    s->nb_streams         = streams;
+    s->nb_stereo_streams  = stereo_streams;
+
+    return 0;
+fail:
+    av_channel_layout_uninit(&layout);
+    return ret;
+}
+