lavf: Add WebM DASH Manifest Muxer

This patch adds the ability to generate WebM DASH manifest XML using
ffmpeg. A sample command line would be as follows:

ffmpeg \
  -f webm_dash_manifest -i video1.webm \
  -f webm_dash_manifest -i video2.webm \
  -f webm_dash_manifest -i audio1.webm \
  -f webm_dash_manifest -i audio2.webm \
  -map 0 -map 1 -map 2 -map 3 \
  -c copy \
  -f webm_dash_manifest \
  -adaptation_sets “id=0,streams=0,1 id=1,streams=2,3” \
  manifest.xml

It works by exporting necessary fields as metadata tags in matroskadec
and use those values to write the appropriate XML fields as per the WebM
DASH Specification [1]. Some ideas are adopted from webm-tools project
[2].

[1]
https://sites.google.com/a/webmproject.org/wiki/adaptive-streaming/webm-dash-specification
[2]
https://chromium.googlesource.com/webm/webm-tools/+/master/webm_dash_manifest/

Signed-off-by: Vignesh Venkatasubramanian <vigneshv@google.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

1 files changed, 317 insertions, 0 deletions

diff --git a/libavformat/webmdashenc.c b/libavformat/webmdashenc.c
new file mode 100644
index 0000000000..381efb7888
--- /dev/null
+++ b/libavformat/webmdashenc.c
@@ -0,0 +1,317 @@
+/*
+ * WebM DASH Manifest XML muxer
+ * Copyright (c) 2014 Vignesh Venkatasubramanian
+ *
+ * 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
+ */
+
+/*
+ * WebM DASH Specification:
+ * https://sites.google.com/a/webmproject.org/wiki/adaptive-streaming/webm-dash-specification
+ */
+
+#include <stdint.h>
+#include <string.h>
+
+#include "avformat.h"
+#include "avio_internal.h"
+#include "matroska.h"
+
+#include "libavutil/avstring.h"
+#include "libavutil/dict.h"
+#include "libavutil/opt.h"
+
+typedef struct AdaptationSet {
+    char id[10];
+    int *streams;
+    int nb_streams;
+} AdaptationSet;
+
+typedef struct WebMDashMuxContext {
+    const AVClass  *class;
+    char *adaptation_sets;
+    AdaptationSet *as;
+    int nb_as;
+} WebMDashMuxContext;
+
+static const char *get_codec_name(int codec_id)
+{
+    switch (codec_id) {
+        case AV_CODEC_ID_VP8:
+            return "vp8";
+        case AV_CODEC_ID_VP9:
+            return "vp9";
+        case AV_CODEC_ID_VORBIS:
+            return "vorbis";
+        case AV_CODEC_ID_OPUS:
+            return "opus";
+    }
+    return NULL;
+}
+
+static double get_duration(AVFormatContext *s)
+{
+    int i = 0;
+    double max = 0.0;
+    for (i = 0; i < s->nb_streams; i++) {
+        AVDictionaryEntry *duration = av_dict_get(s->streams[i]->metadata,
+                                                  DURATION, NULL, 0);
+        if (duration == NULL || atof(duration->value) < 0) continue;
+        if (atof(duration->value) > max) max = atof(duration->value);
+    }
+    return max / 1000;
+}
+
+static void write_header(AVFormatContext *s)
+{
+    double min_buffer_time = 1.0;
+    avio_printf(s->pb, "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
+    avio_printf(s->pb, "<MPD\n");
+    avio_printf(s->pb, "  xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"\n");
+    avio_printf(s->pb, "  xmlns=\"urn:mpeg:DASH:schema:MPD:2011\"\n");
+    avio_printf(s->pb, "  xsi:schemaLocation=\"urn:mpeg:DASH:schema:MPD:2011\"\n");
+    avio_printf(s->pb, "  type=\"static\"\n");
+    avio_printf(s->pb, "  mediaPresentationDuration=\"PT%gS\"\n",
+                get_duration(s));
+    avio_printf(s->pb, "  minBufferTime=\"PT%gS\"\n",
+                min_buffer_time);
+    avio_printf(s->pb, "  profiles=\"urn:webm:dash:profile:webm-on-demand:2012\"");
+    avio_printf(s->pb, ">\n");
+}
+
+static void write_footer(AVFormatContext *s)
+{
+    avio_printf(s->pb, "</MPD>");
+}
+
+static int subsegment_alignment(AVFormatContext *s, AdaptationSet *as) {
+    int i;
+    AVDictionaryEntry *gold = av_dict_get(s->streams[as->streams[0]]->metadata,
+                                          CUE_TIMESTAMPS, NULL, 0);
+    if (gold == NULL) return 0;
+    for (i = 1; i < as->nb_streams; i++) {
+        AVDictionaryEntry *ts = av_dict_get(s->streams[as->streams[i]]->metadata,
+                                            CUE_TIMESTAMPS, NULL, 0);
+        if (ts == NULL || strncmp(gold->value, ts->value, strlen(gold->value))) return 0;
+    }
+    return 1;
+}
+
+static int bitstream_switching(AVFormatContext *s, AdaptationSet *as) {
+    int i;
+    AVDictionaryEntry *gold_track_num = av_dict_get(s->streams[as->streams[0]]->metadata,
+                                                    TRACK_NUMBER, NULL, 0);
+    AVCodecContext *gold_codec = s->streams[as->streams[0]]->codec;
+    if (gold_track_num == NULL) return 0;
+    for (i = 1; i < as->nb_streams; i++) {
+        AVDictionaryEntry *track_num = av_dict_get(s->streams[as->streams[i]]->metadata,
+                                                   TRACK_NUMBER, NULL, 0);
+        AVCodecContext *codec = s->streams[as->streams[i]]->codec;
+        if (track_num == NULL ||
+            strncmp(gold_track_num->value, track_num->value, strlen(gold_track_num->value)) ||
+            gold_codec->codec_id != codec->codec_id ||
+            gold_codec->extradata_size != codec->extradata_size ||
+            memcmp(gold_codec->extradata, codec->extradata, codec->extradata_size)) {
+            return 0;
+        }
+    }
+    return 1;
+}
+
+/*
+ * Writes an Adaptation Set. Returns 0 on success and < 0 on failure.
+ */
+static int write_adaptation_set(AVFormatContext *s, int as_index)
+{
+    WebMDashMuxContext *w = s->priv_data;
+    AdaptationSet *as = &w->as[as_index];
+    AVCodecContext *codec = s->streams[as->streams[0]]->codec;
+    int i;
+    static const char boolean[2][6] = { "false", "true" };
+    int subsegmentStartsWithSAP = 1;
+    AVDictionaryEntry *lang;
+    avio_printf(s->pb, "<AdaptationSet id=\"%s\"", as->id);
+    avio_printf(s->pb, " mimeType=\"%s/webm\"",
+                codec->codec_type == AVMEDIA_TYPE_VIDEO ? "video" : "audio");
+    avio_printf(s->pb, " codecs=\"%s\"", get_codec_name(codec->codec_id));
+
+    lang = av_dict_get(s->streams[as->streams[0]]->metadata, "language", NULL, 0);
+    if (lang != NULL) avio_printf(s->pb, " lang=\"%s\"", lang->value);
+
+    if (codec->codec_type == AVMEDIA_TYPE_VIDEO) {
+        avio_printf(s->pb, " width=\"%d\"", codec->width);
+        avio_printf(s->pb, " height=\"%d\"", codec->height);
+    } else {
+        avio_printf(s->pb, " audioSamplingRate=\"%d\"", codec->sample_rate);
+    }
+
+    avio_printf(s->pb, " bitstreamSwitching=\"%s\"",
+                boolean[bitstream_switching(s, as)]);
+    avio_printf(s->pb, " subsegmentAlignment=\"%s\"",
+                boolean[subsegment_alignment(s, as)]);
+
+    for (i = 0; i < as->nb_streams; i++) {
+        AVDictionaryEntry *kf = av_dict_get(s->streams[as->streams[i]]->metadata,
+                                            CLUSTER_KEYFRAME, NULL, 0);
+        if (kf == NULL || !strncmp(kf->value, "0", 1)) subsegmentStartsWithSAP = 0;
+    }
+    avio_printf(s->pb, " subsegmentStartsWithSAP=\"%d\"", subsegmentStartsWithSAP);
+    avio_printf(s->pb, ">\n");
+
+    for (i = 0; i < as->nb_streams; i++) {
+        AVStream *stream = s->streams[as->streams[i]];
+        AVDictionaryEntry *irange = av_dict_get(stream->metadata, INITIALIZATION_RANGE, NULL, 0);
+        AVDictionaryEntry *cues_start = av_dict_get(stream->metadata, CUES_START, NULL, 0);
+        AVDictionaryEntry *cues_end = av_dict_get(stream->metadata, CUES_END, NULL, 0);
+        AVDictionaryEntry *filename = av_dict_get(stream->metadata, FILENAME, NULL, 0);
+        AVDictionaryEntry *bandwidth = av_dict_get(stream->metadata, BANDWIDTH, NULL, 0);
+        if (irange == NULL || cues_start == NULL || cues_end == NULL || filename == NULL ||
+            bandwidth == NULL) {
+            return -1;
+        }
+        avio_printf(s->pb, "<Representation id=\"%d\"", i);
+        avio_printf(s->pb, " bandwidth=\"%s\"", bandwidth->value);
+        avio_printf(s->pb, ">\n");
+        avio_printf(s->pb, "<BaseURL>%s</BaseURL>\n", filename->value);
+        avio_printf(s->pb, "<SegmentBase\n");
+        avio_printf(s->pb, "  indexRange=\"%s-%s\">\n", cues_start->value, cues_end->value);
+        avio_printf(s->pb, "<Initialization\n");
+        avio_printf(s->pb, "  range=\"0-%s\" />\n", irange->value);
+        avio_printf(s->pb, "</SegmentBase>\n");
+        avio_printf(s->pb, "</Representation>\n");
+    }
+    avio_printf(s->pb, "</AdaptationSet>\n");
+    return 0;
+}
+
+static int to_integer(char *p, int len)
+{
+    int ret;
+    char *q = av_malloc(sizeof(char) * len);
+    if (q == NULL) return -1;
+    strncpy(q, p, len);
+    ret = atoi(q);
+    av_free(q);
+    return ret;
+}
+
+static int parse_adaptation_sets(AVFormatContext *s)
+{
+    WebMDashMuxContext *w = s->priv_data;
+    char *p = w->adaptation_sets;
+    char *q;
+    enum { new_set, parsed_id, parsing_streams } state;
+    // syntax id=0,streams=0,1,2 id=1,streams=3,4 and so on
+    state = new_set;
+    while (p < w->adaptation_sets + strlen(w->adaptation_sets)) {
+        if (*p == ' ')
+            continue;
+        else if (state == new_set && !strncmp(p, "id=", 3)) {
+            w->as = av_realloc(w->as, sizeof(*w->as) * ++w->nb_as);
+            if (w->as == NULL) return -1;
+            w->as[w->nb_as - 1].nb_streams = 0;
+            w->as[w->nb_as - 1].streams = NULL;
+            p += 3; // consume "id="
+            q = w->as[w->nb_as - 1].id;
+            while (*p != ',') *q++ = *p++;
+            *q = 0;
+            p++;
+            state = parsed_id;
+        } else if (state == parsed_id && !strncmp(p, "streams=", 8)) {
+            p += 8; // consume "streams="
+            state = parsing_streams;
+        } else if (state == parsing_streams) {
+            struct AdaptationSet *as = &w->as[w->nb_as - 1];
+            q = p;
+            while (*q != '\0' && *q != ',' && *q != ' ') q++;
+            as->streams = av_realloc(as->streams, sizeof(*as->streams) * ++as->nb_streams);
+            if (as->streams == NULL) return -1;
+            as->streams[as->nb_streams - 1] = to_integer(p, q - p);
+            if (as->streams[as->nb_streams - 1] < 0) return -1;
+            if (*q == '\0') break;
+            if (*q == ' ') state = new_set;
+            p = ++q;
+        } else {
+            return -1;
+        }
+    }
+    return 0;
+}
+
+static int webm_dash_manifest_write_header(AVFormatContext *s)
+{
+    int i;
+    double start = 0.0;
+    WebMDashMuxContext *w = s->priv_data;
+    parse_adaptation_sets(s);
+    write_header(s);
+    avio_printf(s->pb, "<Period id=\"0\"");
+    avio_printf(s->pb, " start=\"PT%gS\"", start);
+    avio_printf(s->pb, " duration=\"PT%gS\"", get_duration(s));
+    avio_printf(s->pb, " >\n");
+
+    for (i = 0; i < w->nb_as; i++) {
+        if (write_adaptation_set(s, i) < 0) return -1;
+    }
+
+    avio_printf(s->pb, "</Period>\n");
+    write_footer(s);
+    return 0;
+}
+
+static int webm_dash_manifest_write_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    return AVERROR_EOF;
+}
+
+static int webm_dash_manifest_write_trailer(AVFormatContext *s)
+{
+    WebMDashMuxContext *w = s->priv_data;
+    int i;
+    for (i = 0; i < w->nb_as; i++) {
+        av_freep(&w->as[i].streams);
+    }
+    av_freep(&w->as);
+    return 0;
+}
+
+#define OFFSET(x) offsetof(WebMDashMuxContext, x)
+static const AVOption options[] = {
+    { "adaptation_sets", "Adaptation sets. Syntax: id=0,streams=0,1,2 id=1,streams=3,4 and so on", OFFSET(adaptation_sets), AV_OPT_TYPE_STRING, { 0 }, 0, 0, AV_OPT_FLAG_ENCODING_PARAM },
+    { NULL },
+};
+
+#if CONFIG_WEBM_DASH_MANIFEST_MUXER
+static const AVClass webm_dash_class = {
+    .class_name = "WebM DASH Manifest muxer",
+    .item_name  = av_default_item_name,
+    .option     = options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+AVOutputFormat ff_webm_dash_manifest_muxer = {
+    .name              = "webm_dash_manifest",
+    .long_name         = NULL_IF_CONFIG_SMALL("WebM DASH Manifest"),
+    .mime_type         = "application/xml",
+    .extensions        = "xml",
+    .priv_data_size    = sizeof(WebMDashMuxContext),
+    .write_header      = webm_dash_manifest_write_header,
+    .write_packet      = webm_dash_manifest_write_packet,
+    .write_trailer     = webm_dash_manifest_write_trailer,
+    .priv_class        = &webm_dash_class,
+};
+#endif