libavformat/webm_chunk.c - ffmpeg - Git at Google

 /*
  * 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 "avio_internal.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;
     char *http_method;
     uint64_t duration_written;
     int64_t prev_pts;
     ff_const59 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[MAX_FILENAME_SIZE])
 {
     WebMChunkContext *wc = s->priv_data;
     AVFormatContext *oc = wc->avf;
     if (!filename) {
         return AVERROR(EINVAL);
     }
     if (is_header) {
         int len;
         if (!wc->header_filename) {
             av_log(oc, AV_LOG_ERROR, "No header filename provided\n");
             return AVERROR(EINVAL);
         }
         len = av_strlcpy(filename, wc->header_filename, MAX_FILENAME_SIZE);
         if (len >= MAX_FILENAME_SIZE) {
             av_log(oc, AV_LOG_ERROR, "Header filename too long\n");
             return AVERROR(EINVAL);
         }
     } else {
         if (av_get_frame_filename(filename, MAX_FILENAME_SIZE,
                                   s->url, wc->chunk_index - 1) < 0) {
             av_log(oc, AV_LOG_ERROR, "Invalid chunk filename template '%s'\n", s->url);
             return AVERROR(EINVAL);
         }
     }
     return 0;
 }

 static int webm_chunk_write_header(AVFormatContext *s)
 {
     WebMChunkContext *wc = s->priv_data;
     AVFormatContext *oc = NULL;
     int ret;
     int i;
     AVDictionary *options = NULL;
     char oc_filename[MAX_FILENAME_SIZE];
     char *oc_url;

     // 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->url, "video/webm");
     if (!wc->oformat)
         return AVERROR_MUXER_NOT_FOUND;
     wc->prev_pts = AV_NOPTS_VALUE;

     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;
     oc_url = av_strdup(oc_filename);
     if (!oc_url)
         return AVERROR(ENOMEM);
     ff_format_set_url(oc, oc_url);
     if (wc->http_method)
         av_dict_set(&options, "method", wc->http_method, 0);
     ret = s->io_open(s, &oc->pb, oc->url, AVIO_FLAG_WRITE, &options);
     av_dict_free(&options);
     if (ret < 0)
         return ret;

     oc->pb->seekable = 0;
     ret = oc->oformat->write_header(oc);
     if (ret < 0)
         return ret;
     ff_format_io_close(s, &oc->pb);
     for (i = 0; i < s->nb_streams; i++) {
         // ms precision is the de-facto standard timescale for mkv files.
         avpriv_set_pts_info(s->streams[i], 64, 1, 1000);
     }
     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, int flush)
 {
     WebMChunkContext *wc = s->priv_data;
     AVFormatContext *oc = wc->avf;
     int ret;
     int buffer_size;
     uint8_t *buffer;
     AVIOContext *pb;
     char filename[MAX_FILENAME_SIZE];
     AVDictionary *options = NULL;

     if (!oc->pb)
         return 0;

     if (flush)
         // Flush the cluster in WebM muxer.
         oc->oformat->write_packet(oc, NULL);
     buffer_size = avio_close_dyn_buf(oc->pb, &buffer);
     oc->pb = NULL;
     ret = get_chunk_filename(s, 0, filename);
     if (ret < 0)
         goto fail;
     if (wc->http_method)
         av_dict_set(&options, "method", wc->http_method, 0);
     ret = s->io_open(s, &pb, filename, AVIO_FLAG_WRITE, &options);
     if (ret < 0)
         goto fail;
     avio_write(pb, buffer, buffer_size);
     ff_format_io_close(s, &pb);
 fail:
     av_dict_free(&options);
     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->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
         if (wc->prev_pts != AV_NOPTS_VALUE)
             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. Also, a new chunk is started
     // unconditionally if there is no currently open chunk.
     if (!oc->pb || (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO &&
          (pkt->flags & AV_PKT_FLAG_KEY)) ||
         (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO &&
          wc->duration_written >= wc->chunk_duration)) {
         wc->duration_written = 0;
         if ((ret = chunk_end(s, 1)) < 0 || (ret = chunk_start(s)) < 0) {
             return ret;
         }
     }

     ret = oc->oformat->write_packet(oc, pkt);

     return ret;
 }

 static int webm_chunk_write_trailer(AVFormatContext *s)
 {
     WebMChunkContext *wc = s->priv_data;
     AVFormatContext *oc = wc->avf;
     int ret;

     if (!oc->pb) {
         ret = chunk_start(s);
         if (ret < 0)
             goto fail;
     }
     oc->oformat->write_trailer(oc);
     ret = chunk_end(s, 0);
 fail:
     oc->streams = NULL;
     oc->nb_streams = 0;
     avformat_free_context(oc);
     return ret;
 }

 #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 },
     { "method", "set the HTTP method", OFFSET(http_method), AV_OPT_TYPE_STRING, {.str = NULL},  0, 0, 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
	/*
	* 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 "avio_internal.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;
	char *http_method;
	uint64_t duration_written;
	int64_t prev_pts;
	ff_const59 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[MAX_FILENAME_SIZE])
	{
	WebMChunkContext *wc = s->priv_data;
	AVFormatContext *oc = wc->avf;
	if (!filename) {
	return AVERROR(EINVAL);
	}
	if (is_header) {
	int len;
	if (!wc->header_filename) {
	av_log(oc, AV_LOG_ERROR, "No header filename provided\n");
	return AVERROR(EINVAL);
	}
	len = av_strlcpy(filename, wc->header_filename, MAX_FILENAME_SIZE);
	if (len >= MAX_FILENAME_SIZE) {
	av_log(oc, AV_LOG_ERROR, "Header filename too long\n");
	return AVERROR(EINVAL);
	}
	} else {
	if (av_get_frame_filename(filename, MAX_FILENAME_SIZE,
	s->url, wc->chunk_index - 1) < 0) {
	av_log(oc, AV_LOG_ERROR, "Invalid chunk filename template '%s'\n", s->url);
	return AVERROR(EINVAL);
	}
	}
	return 0;
	}

	static int webm_chunk_write_header(AVFormatContext *s)
	{
	WebMChunkContext *wc = s->priv_data;
	AVFormatContext *oc = NULL;
	int ret;
	int i;
	AVDictionary *options = NULL;
	char oc_filename[MAX_FILENAME_SIZE];
	char *oc_url;

	// 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->url, "video/webm");
	if (!wc->oformat)
	return AVERROR_MUXER_NOT_FOUND;
	wc->prev_pts = AV_NOPTS_VALUE;

	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;
	oc_url = av_strdup(oc_filename);
	if (!oc_url)
	return AVERROR(ENOMEM);
	ff_format_set_url(oc, oc_url);
	if (wc->http_method)
	av_dict_set(&options, "method", wc->http_method, 0);
	ret = s->io_open(s, &oc->pb, oc->url, AVIO_FLAG_WRITE, &options);
	av_dict_free(&options);
	if (ret < 0)
	return ret;

	oc->pb->seekable = 0;
	ret = oc->oformat->write_header(oc);
	if (ret < 0)
	return ret;
	ff_format_io_close(s, &oc->pb);
	for (i = 0; i < s->nb_streams; i++) {
	// ms precision is the de-facto standard timescale for mkv files.
	avpriv_set_pts_info(s->streams[i], 64, 1, 1000);
	}
	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, int flush)
	{
	WebMChunkContext *wc = s->priv_data;
	AVFormatContext *oc = wc->avf;
	int ret;
	int buffer_size;
	uint8_t *buffer;
	AVIOContext *pb;
	char filename[MAX_FILENAME_SIZE];
	AVDictionary *options = NULL;

	if (!oc->pb)
	return 0;

	if (flush)
	// Flush the cluster in WebM muxer.
	oc->oformat->write_packet(oc, NULL);
	buffer_size = avio_close_dyn_buf(oc->pb, &buffer);
	oc->pb = NULL;
	ret = get_chunk_filename(s, 0, filename);
	if (ret < 0)
	goto fail;
	if (wc->http_method)
	av_dict_set(&options, "method", wc->http_method, 0);
	ret = s->io_open(s, &pb, filename, AVIO_FLAG_WRITE, &options);
	if (ret < 0)
	goto fail;
	avio_write(pb, buffer, buffer_size);
	ff_format_io_close(s, &pb);
	fail:
	av_dict_free(&options);
	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->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
	if (wc->prev_pts != AV_NOPTS_VALUE)
	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. Also, a new chunk is started
	// unconditionally if there is no currently open chunk.
	if (!oc->pb \|\| (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO &&
	(pkt->flags & AV_PKT_FLAG_KEY)) \|\|
	(st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO &&
	wc->duration_written >= wc->chunk_duration)) {
	wc->duration_written = 0;
	if ((ret = chunk_end(s, 1)) < 0 \|\| (ret = chunk_start(s)) < 0) {
	return ret;
	}
	}

	ret = oc->oformat->write_packet(oc, pkt);

	return ret;
	}

	static int webm_chunk_write_trailer(AVFormatContext *s)
	{
	WebMChunkContext *wc = s->priv_data;
	AVFormatContext *oc = wc->avf;
	int ret;

	if (!oc->pb) {
	ret = chunk_start(s);
	if (ret < 0)
	goto fail;
	}
	oc->oformat->write_trailer(oc);
	ret = chunk_end(s, 0);
	fail:
	oc->streams = NULL;
	oc->nb_streams = 0;
	avformat_free_context(oc);
	return ret;
	}

	#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 },
	{ "method", "set the HTTP method", OFFSET(http_method), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, 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