/*
* 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"
#define MAX_FILENAME_SIZE 1024
typedef struct WebMChunkContext {
const AVClass *class;
int chunk_start_index;
char *header_filename;
int chunk_duration;
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);
*(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 get_chunk_filename(AVFormatContext *s, int is_header, char *filename)
{
WebMChunkContext *wc = s->priv_data;
AVFormatContext *oc = wc->avf;
if (!filename) {
return AVERROR(EINVAL);
}
if (is_header) {
if (!wc->header_filename) {
return AVERROR(EINVAL);
}
av_strlcpy
(filename
, wc
->header_filename
, strlen(wc
->header_filename
) + 1); } else {
if (av_get_frame_filename(filename, MAX_FILENAME_SIZE,
s->filename, wc->chunk_index - 1) < 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_index = wc->chunk_start_index;
wc->oformat = av_guess_format("webm", s->filename, "video/webm");
if (!wc->oformat)
return AVERROR_MUXER_NOT_FOUND;
ret = chunk_mux_init(s);
if (ret < 0)
return ret;
oc = wc->avf;
ret = get_chunk_filename(s, 1, oc->filename);
if (ret < 0)
return ret;
ret = avio_open2(&oc->pb, oc->filename, AVIO_FLAG_WRITE,
&s->interrupt_callback, NULL);
if (ret < 0)
return ret;
oc->pb->seekable = 0;
ret = oc->oformat->write_header(oc);
if (ret < 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;
ret = avio_open_dyn_buf(&oc->pb);
if (ret < 0)
return ret;
wc->chunk_index++;
return 0;
}
static int chunk_end(AVFormatContext *s)
{
WebMChunkContext *wc = s->priv_data;
AVFormatContext *oc = wc->avf;
int ret;
int buffer_size;
uint8_t *buffer;
AVIOContext *pb;
char filename[MAX_FILENAME_SIZE];
if (wc->chunk_start_index == wc->chunk_index)
return 0;
// Flush the cluster in WebM muxer.
oc->oformat->write_packet(oc, NULL);
buffer_size = avio_close_dyn_buf(oc->pb, &buffer);
ret = get_chunk_filename(s, 0, filename);
if (ret < 0)
goto fail;
ret = avio_open2(&pb, filename, AVIO_FLAG_WRITE, &s->interrupt_callback, NULL);
if (ret < 0)
goto fail;
avio_write(pb, buffer, buffer_size);
ret = avio_close(pb);
if (ret < 0)
goto fail;
oc->pb = NULL;
fail:
av_free(buffer);
return (ret < 0) ? ret : 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;
}
}
ret = oc->oformat->write_packet(oc, pkt);
if (ret < 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,
.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