[FFmpeg-devel] [PATCH] lavf: Add support for WebM Live Muxing
wm4
nfxjfg at googlemail.com
Tue Mar 31 00:33:58 CEST 2015
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?
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