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-rw-r--r--libavformat/webm_chunk.c264
1 files changed, 264 insertions, 0 deletions
diff --git a/libavformat/webm_chunk.c b/libavformat/webm_chunk.c
new file mode 100644
index 0000000000..063eb3beb8
--- /dev/null
+++ b/libavformat/webm_chunk.c
@@ -0,0 +1,264 @@
+/*
+ * 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;
+ 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 = s->io_open(s, &oc->pb, oc->filename, AVIO_FLAG_WRITE, NULL);
+ 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);
+ 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 = s->io_open(s, &pb, filename, AVIO_FLAG_WRITE, NULL);
+ if (ret < 0)
+ goto fail;
+ avio_write(pb, buffer, buffer_size);
+ ff_format_io_close(s, &pb);
+ 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
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