[FFmpeg-devel] [PATCH] lavf: Add support for WebM Live Muxing
Vignesh Venkatasubramanian
vigneshv at google.com
Tue Mar 31 01:19:56 CEST 2015
On Mon, Mar 30, 2015 at 3:33 PM, wm4 <nfxjfg at googlemail.com> wrote:
> On Mon, 30 Mar 2015 12:49:45 -0700
> Vignesh Venkatasubramanian <vigneshv at google.com> wrote:
>
>> This patch adds support for WebM Live Muxing by adding a new WebM
>> Chunk muxer. It writes out live WebM Chunks which can be used for
>> playback using Live DASH Clients.
>>
>> Please see muxers.texi for sample usage.
>>
>> Signed-off-by: Vignesh Venkatasubramanian <vigneshv at google.com>
>> ---
>> Changelog | 1 +
>> doc/muxers.texi | 43 ++++++++
>> libavformat/Makefile | 5 +-
>> libavformat/allformats.c | 1 +
>> libavformat/matroskaenc.c | 12 ++-
>> libavformat/version.h | 2 +-
>> libavformat/webm_chunk.c | 251 ++++++++++++++++++++++++++++++++++++++++++++++
>> 7 files changed, 309 insertions(+), 6 deletions(-)
>> create mode 100644 libavformat/webm_chunk.c
>>
>> diff --git a/Changelog b/Changelog
>> index 75da156..2c7f283 100644
>> --- a/Changelog
>> +++ b/Changelog
>> @@ -12,6 +12,7 @@ version <next>:
>> - Detelecine filter
>> - Intel QSV-accelerated H.264 encoding
>> - MMAL-accelerated H.264 decoding
>> +- WebM Live Chunk Muxer
>>
>>
>> version 2.6:
>> diff --git a/doc/muxers.texi b/doc/muxers.texi
>> index a8225fc..d9d900b 100644
>> --- a/doc/muxers.texi
>> +++ b/doc/muxers.texi
>> @@ -1236,4 +1236,47 @@ ffmpeg -f webm_dash_manifest -i video1.webm \
>> manifest.xml
>> @end example
>>
>> + at section webm_chunk
>> +
>> +WebM Live Chunk Muxer.
>> +
>> +This muxer writes out WebM headers and chunks as separate files which can be
>> +consumed by clients that support WebM Live streams via DASH.
>> +
>> + at subsection Options
>> +
>> +This muxer supports the following options:
>> +
>> + at table @option
>> + at item chunk_start_index
>> +Index of the first chunk (defaults to 0).
>> +
>> + at item header
>> +Filename of the header where the initialization data will be written.
>> +
>> + at item audio_chunk_duration
>> +Duration of each audio chunk in milliseconds (defaults to 5000).
>> + at end table
>> +
>> + at subsection Example
>> + at example
>> +ffmpeg -f v4l2 -i /dev/video0 \
>> + -f alsa -i hw:0 \
>> + -map 0:0 \
>> + -c:v libvpx-vp9 \
>> + -s 640x360 -keyint_min 30 -g 30 \
>> + -f webm_chunk \
>> + -header webm_live_video_360.hdr \
>> + -chunk_start_index 1 \
>> + webm_live_video_360_%d.chk \
>> + -map 1:0 \
>> + -c:a libvorbis \
>> + -b:a 128k \
>> + -f webm_chunk \
>> + -header webm_live_audio_128.hdr \
>> + -chunk_start_index 1 \
>> + -audio_chunk_duration 1000 \
>> + webm_live_audio_128_%d.chk
>> + at end example
>> +
>> @c man end MUXERS
>> diff --git a/libavformat/Makefile b/libavformat/Makefile
>> index 2118ff2..e40ed4d 100644
>> --- a/libavformat/Makefile
>> +++ b/libavformat/Makefile
>> @@ -237,7 +237,7 @@ OBJS-$(CONFIG_MATROSKA_DEMUXER) += matroskadec.o matroska.o \
>> OBJS-$(CONFIG_MATROSKA_MUXER) += matroskaenc.o matroska.o \
>> isom.o avc.o hevc.o \
>> flacenc_header.o avlanguage.o vorbiscomment.o wv.o \
>> - webmdashenc.o
>> + webmdashenc.o webm_chunk.o
>> OBJS-$(CONFIG_MD5_MUXER) += md5enc.o
>> OBJS-$(CONFIG_MGSTS_DEMUXER) += mgsts.o
>> OBJS-$(CONFIG_MICRODVD_DEMUXER) += microdvddec.o subtitles.o
>> @@ -451,12 +451,13 @@ OBJS-$(CONFIG_WEBM_MUXER) += matroskaenc.o matroska.o \
>> isom.o avc.o hevc.o \
>> flacenc_header.o avlanguage.o \
>> wv.o vorbiscomment.o \
>> - webmdashenc.o
>> + webmdashenc.o webm_chunk.o
>> OBJS-$(CONFIG_WEBM_DASH_MANIFEST_DEMUXER)+= matroskadec.o matroska.o \
>> isom.o rmsipr.o flac_picture.o \
>> oggparsevorbis.o vorbiscomment.o \
>> flac_picture.o replaygain.o
>> OBJS-$(CONFIG_WEBM_DASH_MANIFEST_MUXER) += webmdashenc.o matroska.o
>> +OBJS-$(CONFIG_WEBM_CHUNK_MUXER) += webm_chunk.o matroska.o
>> OBJS-$(CONFIG_WEBP_MUXER) += webpenc.o
>> OBJS-$(CONFIG_WEBVTT_DEMUXER) += webvttdec.o subtitles.o
>> OBJS-$(CONFIG_WEBVTT_MUXER) += webvttenc.o
>> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
>> index 26ccc27..f56493c 100644
>> --- a/libavformat/allformats.c
>> +++ b/libavformat/allformats.c
>> @@ -316,6 +316,7 @@ void av_register_all(void)
>> REGISTER_DEMUXER (WC3, wc3);
>> REGISTER_MUXER (WEBM, webm);
>> REGISTER_MUXDEMUX(WEBM_DASH_MANIFEST, webm_dash_manifest);
>> + REGISTER_MUXER (WEBM_CHUNK, webm_chunk);
>> REGISTER_MUXER (WEBP, webp);
>> REGISTER_MUXDEMUX(WEBVTT, webvtt);
>> REGISTER_DEMUXER (WSAUD, wsaud);
>> diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
>> index 6b2e390..027605e 100644
>> --- a/libavformat/matroskaenc.c
>> +++ b/libavformat/matroskaenc.c
>> @@ -120,6 +120,7 @@ typedef struct MatroskaMuxContext {
>> int64_t cluster_time_limit;
>> int is_dash;
>> int dash_track_number;
>> + int is_live;
>>
>> uint32_t chapter_id_offset;
>> int wrote_chapters;
>> @@ -1407,7 +1408,9 @@ static int mkv_write_header(AVFormatContext *s)
>> // reserve space for the duration
>> mkv->duration = 0;
>> mkv->duration_offset = avio_tell(pb);
>> - put_ebml_void(pb, 11); // assumes double-precision float to be written
>> + if (!mkv->is_live) {
>> + put_ebml_void(pb, 11); // assumes double-precision float to be written
>> + }
>> end_ebml_master(pb, segment_info);
>>
>> ret = mkv_write_tracks(s);
>> @@ -1431,7 +1434,7 @@ static int mkv_write_header(AVFormatContext *s)
>> return ret;
>> }
>>
>> - if (!s->pb->seekable)
>> + if (!s->pb->seekable && !mkv->is_live)
>> mkv_write_seekhead(pb, mkv->main_seekhead);
>>
>> mkv->cues = mkv_start_cues(mkv->segment_offset);
>> @@ -1950,7 +1953,9 @@ static int mkv_write_trailer(AVFormatContext *s)
>> avio_seek(pb, currentpos, SEEK_SET);
>> }
>>
>> - end_ebml_master(pb, mkv->segment);
>> + if (!mkv->is_live) {
>> + end_ebml_master(pb, mkv->segment);
>> + }
>> av_freep(&mkv->tracks);
>> av_freep(&mkv->cues->entries);
>> av_freep(&mkv->cues);
>> @@ -2014,6 +2019,7 @@ static const AVOption options[] = {
>> { "cluster_time_limit", "Store at most the provided number of milliseconds in a cluster.", OFFSET(cluster_time_limit), AV_OPT_TYPE_INT64, { .i64 = -1 }, -1, INT64_MAX, FLAGS },
>> { "dash", "Create a WebM file conforming to WebM DASH specification", OFFSET(is_dash), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, FLAGS },
>> { "dash_track_number", "Track number for the DASH stream", OFFSET(dash_track_number), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 127, FLAGS },
>> + { "live", "Write files assuming it is a live stream.", OFFSET(is_live), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, FLAGS },
>> { "allow_raw_vfw", "allow RAW VFW mode", OFFSET(allow_raw_vfw), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, FLAGS },
>> { NULL },
>> };
>> diff --git a/libavformat/version.h b/libavformat/version.h
>> index a183d7f..ff85227 100644
>> --- a/libavformat/version.h
>> +++ b/libavformat/version.h
>> @@ -30,7 +30,7 @@
>> #include "libavutil/version.h"
>>
>> #define LIBAVFORMAT_VERSION_MAJOR 56
>> -#define LIBAVFORMAT_VERSION_MINOR 26
>> +#define LIBAVFORMAT_VERSION_MINOR 27
>> #define LIBAVFORMAT_VERSION_MICRO 101
>>
>> #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
>> diff --git a/libavformat/webm_chunk.c b/libavformat/webm_chunk.c
>> new file mode 100644
>> index 0000000..1c7cd00
>> --- /dev/null
>> +++ b/libavformat/webm_chunk.c
>> @@ -0,0 +1,251 @@
>> +/*
>> + * Copyright (c) 2015, 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
>> + */
>> +
>> +/**
>> + * @file WebM Chunk Muxer
>> + * The chunk muxer enables writing WebM Live chunks where there is a header
>> + * chunk, followed by data chunks where each Cluster is written out as a Chunk.
>> + */
>> +
>> +#include <float.h>
>> +#include <time.h>
>> +
>> +#include "avformat.h"
>> +#include "avio.h"
>> +#include "internal.h"
>> +
>> +#include "libavutil/avassert.h"
>> +#include "libavutil/log.h"
>> +#include "libavutil/opt.h"
>> +#include "libavutil/avstring.h"
>> +#include "libavutil/parseutils.h"
>> +#include "libavutil/mathematics.h"
>> +#include "libavutil/time.h"
>> +#include "libavutil/time_internal.h"
>> +#include "libavutil/timestamp.h"
>> +
>> +typedef struct WebMChunkContext {
>> + const AVClass *class;
>> + int chunk_start_index;
>> + char *header_filename;
>> + int chunk_duration;
>> + int chunk_count;
>> + int chunk_index;
>> + uint64_t duration_written;
>> + int prev_pts;
>> + AVOutputFormat *oformat;
>> + AVFormatContext *avf;
>> +} WebMChunkContext;
>> +
>> +static int chunk_mux_init(AVFormatContext *s)
>> +{
>> + WebMChunkContext *wc = s->priv_data;
>> + AVFormatContext *oc;
>> + int ret;
>> +
>> + ret = avformat_alloc_output_context2(&wc->avf, wc->oformat, NULL, NULL);
>> + if (ret < 0)
>> + return ret;
>> + oc = wc->avf;
>> +
>> + oc->interrupt_callback = s->interrupt_callback;
>> + oc->max_delay = s->max_delay;
>> + av_dict_copy(&oc->metadata, s->metadata, 0);
>> +
>> + oc->priv_data = av_mallocz(oc->oformat->priv_data_size);
>> + if (!oc->priv_data) {
>> + avio_close(oc->pb);
>> + return AVERROR(ENOMEM);
>> + }
>> + *(const AVClass**)oc->priv_data = oc->oformat->priv_class;
>> + av_opt_set_defaults(oc->priv_data);
>> + av_opt_set_int(oc->priv_data, "dash", 1, 0);
>> + av_opt_set_int(oc->priv_data, "cluster_time_limit", wc->chunk_duration, 0);
>> + av_opt_set_int(oc->priv_data, "live", 1, 0);
>> +
>> + oc->streams = s->streams;
>> + oc->nb_streams = s->nb_streams;
>> +
>> + return 0;
>> +}
>> +
>> +static int set_chunk_filename(AVFormatContext *s, int is_header)
>> +{
>> + WebMChunkContext *wc = s->priv_data;
>> + AVFormatContext *oc = wc->avf;
>> + if (is_header) {
>> + if (!wc->header_filename) {
>> + return AVERROR(EINVAL);
>> + }
>> + av_strlcpy(oc->filename, wc->header_filename, strlen(wc->header_filename) + 1);
>> + } else {
>> + if (av_get_frame_filename(oc->filename, sizeof(oc->filename),
>> + s->filename, wc->chunk_index) < 0) {
>> + av_log(oc, AV_LOG_ERROR, "Invalid chunk filename template '%s'\n", s->filename);
>> + return AVERROR(EINVAL);
>> + }
>> + }
>> + return 0;
>> +}
>> +
>> +static int webm_chunk_write_header(AVFormatContext *s)
>> +{
>> + WebMChunkContext *wc = s->priv_data;
>> + AVFormatContext *oc = NULL;
>> + int ret;
>> +
>> + // DASH Streams can only have either one track per file.
>> + if (s->nb_streams != 1) { return AVERROR_INVALIDDATA; }
>> +
>> + wc->chunk_count = 0;
>> + wc->chunk_index = wc->chunk_start_index;
>> + wc->oformat = av_guess_format("webm", s->filename, "video/webm");
>> + if (!wc->oformat) { return AVERROR_MUXER_NOT_FOUND; }
>> +
>> + if ((ret = chunk_mux_init(s)) < 0) { return ret; }
>> + oc = wc->avf;
>> + if ((ret = set_chunk_filename(s, 1)) < 0) { return ret; }
>> + if ((ret = avio_open2(&oc->pb, oc->filename, AVIO_FLAG_WRITE,
>> + &s->interrupt_callback, NULL)) < 0) {
>> + return ret;
>> + }
>> + oc->pb->seekable = 0;
>> + if ((ret = oc->oformat->write_header(oc)) < 0) { return ret; }
>> + avio_close(oc->pb);
>> + return 0;
>> +}
>> +
>> +static int chunk_start(AVFormatContext *s)
>> +{
>> + WebMChunkContext *wc = s->priv_data;
>> + AVFormatContext *oc = wc->avf;
>> + int ret;
>> +
>> + if ((ret = set_chunk_filename(s, 0)) < 0) { return ret; }
>> + wc->chunk_index++;
>> + if ((ret = avio_open2(&oc->pb, oc->filename, AVIO_FLAG_WRITE,
>> + &s->interrupt_callback, NULL)) < 0) {
>> + return ret;
>> + }
>> + oc->pb->seekable = 0;
>> + return 0;
>> +}
>> +
>> +static int chunk_end(AVFormatContext *s)
>> +{
>> + WebMChunkContext *wc = s->priv_data;
>> + AVFormatContext *oc = wc->avf;
>> + int ret;
>> +
>> + if (wc->chunk_start_index == wc->chunk_index) { return 0; }
>> + // Flush the cluster in WebM muxer.
>> + oc->oformat->write_packet(oc, NULL);
>> + if ((ret = avio_close(oc->pb)) < 0) {
>> + return ret;
>> + }
>> + wc->chunk_count++;
>> + return 0;
>> +}
>> +
>> +static int webm_chunk_write_packet(AVFormatContext *s, AVPacket *pkt)
>> +{
>> + WebMChunkContext *wc = s->priv_data;
>> + AVFormatContext *oc = wc->avf;
>> + AVStream *st = s->streams[pkt->stream_index];
>> + int ret;
>> +
>> + if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
>> + wc->duration_written += av_rescale_q(pkt->pts - wc->prev_pts,
>> + st->time_base,
>> + (AVRational) {1, 1000});
>> + wc->prev_pts = pkt->pts;
>> + }
>> +
>> + // For video, a new chunk is started only on key frames. For audio, a new
>> + // chunk is started based on chunk_duration.
>> + if ((st->codec->codec_type == AVMEDIA_TYPE_VIDEO &&
>> + (pkt->flags & AV_PKT_FLAG_KEY)) ||
>> + (st->codec->codec_type == AVMEDIA_TYPE_AUDIO &&
>> + (pkt->pts == 0 || wc->duration_written >= wc->chunk_duration))) {
>> + wc->duration_written = 0;
>> + if ((ret = chunk_end(s)) < 0 || (ret = chunk_start(s)) < 0) {
>> + goto fail;
>> + }
>> + }
>> +
>> + if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO && pkt->pts == 0) {
>> + goto fail;
>> + }
>> + if ((ret = oc->oformat->write_packet(oc, pkt)) < 0) {
>> + goto fail;
>> + }
>> +
>> +fail:
>> + if (ret < 0) {
>> + oc->streams = NULL;
>> + oc->nb_streams = 0;
>> + avformat_free_context(oc);
>> + }
>> +
>> + return ret;
>> +}
>> +
>> +static int webm_chunk_write_trailer(AVFormatContext *s)
>> +{
>> + WebMChunkContext *wc = s->priv_data;
>> + AVFormatContext *oc = wc->avf;
>> + oc->oformat->write_trailer(oc);
>> + chunk_end(s);
>> + oc->streams = NULL;
>> + oc->nb_streams = 0;
>> + avformat_free_context(oc);
>> + return 0;
>> +}
>> +
>> +#define OFFSET(x) offsetof(WebMChunkContext, x)
>> +static const AVOption options[] = {
>> + { "chunk_start_index", "start index of the chunk", OFFSET(chunk_start_index), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
>> + { "header", "filename of the header where the initialization data will be written", OFFSET(header_filename), AV_OPT_TYPE_STRING, { 0 }, 0, 0, AV_OPT_FLAG_ENCODING_PARAM },
>> + { "audio_chunk_duration", "duration of each chunk in milliseconds", OFFSET(chunk_duration), AV_OPT_TYPE_INT, {.i64 = 5000}, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
>> + { NULL },
>> +};
>> +
>> +#if CONFIG_WEBM_CHUNK_MUXER
>> +static const AVClass webm_chunk_class = {
>> + .class_name = "WebM Chunk Muxer",
>> + .item_name = av_default_item_name,
>> + .option = options,
>> + .version = LIBAVUTIL_VERSION_INT,
>> +};
>> +
>> +AVOutputFormat ff_webm_chunk_muxer = {
>> + .name = "webm_chunk",
>> + .long_name = NULL_IF_CONFIG_SMALL("WebM Chunk Muxer"),
>> + .mime_type = "video/webm",
>> + .extensions = "chk",
>> + .flags = AVFMT_NOFILE | AVFMT_GLOBALHEADER | AVFMT_NEEDNUMBER |
>> + AVFMT_TS_NONSTRICT | AVFMT_ALLOW_FLUSH,
>> + .priv_data_size = sizeof(WebMChunkContext),
>> + .write_header = webm_chunk_write_header,
>> + .write_packet = webm_chunk_write_packet,
>> + .write_trailer = webm_chunk_write_trailer,
>> + .priv_class = &webm_chunk_class,
>> +};
>> +#endif
>
> When are we going to get a DASH demuxer?
>
I'm trying to get a WebM Live pipeline with FFmpeg and Dash.js. I'll
try and work on the demuxer once i get the muxing pipeline fully
working. And since you asked, this patch will be followed by a few
more patches that will help create live DASH Manifests as well with
FFmpeg.
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
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--
Vignesh
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