/* * 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; 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) { av_log(oc, AV_LOG_ERROR, "No header filename provided\n"); 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; int i; AVDictionary *options = NULL; // 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; if (wc->http_method) av_dict_set(&options, "method", wc->http_method, 0); ret = s->io_open(s, &oc->pb, oc->filename, 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) { 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 (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; 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); oc->pb = NULL; 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) { 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->codecpar->codec_type == AVMEDIA_TYPE_VIDEO && (pkt->flags & AV_PKT_FLAG_KEY)) || (st->codecpar->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 }, { "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