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matroskadec: Add support for parsing live header files 

This patch adds support for parsing live files (produced by
-f webm_chunk) which contains only the headers but no packets. This
is only used when using -f webm_dash_manifest. There will be a
follow up patch which adds live support to WebM DASH Manifest
muxer.

Signed-off-by: Vignesh Venkatasubramanian <vigneshv@google.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Vignesh Venkatasubramanian 2015-03-31 16:51:57 -07:00 committed by Michael Niedermayer
parent afb327caf3
commit 2171b7c58e
1 changed files with 36 additions and 13 deletions
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49
libavformat/matroskadec.c
View File

@ -40,6 +40,7 @@
#include "libavutil/intreadwrite.h"
#include "libavutil/lzo.h"
#include "libavutil/mathematics.h"
#include "libavutil/opt.h"
#include "libavutil/time_internal.h"
#include "libavcodec/bytestream.h"
@ -260,6 +261,7 @@ typedef struct MatroskaLevel1Element {
} MatroskaLevel1Element;
typedef struct MatroskaDemuxContext {
const AVClass *class;
AVFormatContext *ctx;
/* EBML stuff */
@ -307,6 +309,9 @@ typedef struct MatroskaDemuxContext {
/* File has SSA subtitles which prevent incremental cluster parsing. */
int contains_ssa;
/* WebM DASH Manifest live flag/ */
int is_live;
} MatroskaDemuxContext;
typedef struct MatroskaBlock {
@ -698,7 +703,7 @@ static int ebml_level_end(MatroskaDemuxContext *matroska)
return 1;
}
}
return 0;
return (matroska->is_live && matroska->ctx->pb->eof_reached) ? 1 : 0;
}
/*
@ -949,8 +954,11 @@ static int ebml_parse(MatroskaDemuxContext *matroska, EbmlSyntax *syntax,
if (!matroska->current_id) {
uint64_t id;
int res = ebml_read_num(matroska, matroska->ctx->pb, 4, &id);
if (res < 0)
return res;
if (res < 0) {
// in live mode, finish parsing if EOF is reached.
return (matroska->is_live && matroska->ctx->pb->eof_reached &&
res == AVERROR_EOF) ? 1 : res;
}
matroska->current_id = id | 1 << 7 * res;
}
return ebml_parse_id(matroska, syntax, matroska->current_id, data);
@ -3417,26 +3425,27 @@ static int webm_dash_manifest_read_header(AVFormatContext *s)
return -1;
}
// initialization range
// 5 is the offset of Cluster ID.
av_dict_set_int(&s->streams[0]->metadata, INITIALIZATION_RANGE, avio_tell(s->pb) - 5, 0);
if (!matroska->is_live) {
buf = av_asprintf("%g", matroska->duration);
if (!buf) return AVERROR(ENOMEM);
av_dict_set(&s->streams[0]->metadata, DURATION, buf, 0);
av_free(buf);
// initialization range
// 5 is the offset of Cluster ID.
av_dict_set_int(&s->streams[0]->metadata, INITIALIZATION_RANGE, avio_tell(s->pb) - 5, 0);
}
// basename of the file
buf = strrchr(s->filename, '/');
av_dict_set(&s->streams[0]->metadata, FILENAME, buf ? ++buf : s->filename, 0);
// duration
buf = av_asprintf("%g", matroska->duration);
if (!buf) return AVERROR(ENOMEM);
av_dict_set(&s->streams[0]->metadata, DURATION, buf, 0);
av_free(buf);
// track number
tracks = matroska->tracks.elem;
av_dict_set_int(&s->streams[0]->metadata, TRACK_NUMBER, tracks[0].num, 0);
// parse the cues and populate Cue related fields
return webm_dash_manifest_cues(s);
return matroska->is_live ? 0 : webm_dash_manifest_cues(s);
}
static int webm_dash_manifest_read_packet(AVFormatContext *s, AVPacket *pkt)
@ -3444,6 +3453,19 @@ static int webm_dash_manifest_read_packet(AVFormatContext *s, AVPacket *pkt)
return AVERROR_EOF;
}
#define OFFSET(x) offsetof(MatroskaDemuxContext, x)
static const AVOption options[] = {
{ "live", "flag indicating that the input is a live file that only has the headers.", OFFSET(is_live), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, AV_OPT_FLAG_DECODING_PARAM },
{ NULL },
};
static const AVClass webm_dash_class = {
.class_name = "WebM DASH Manifest demuxer",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
AVInputFormat ff_matroska_demuxer = {
.name = "matroska,webm",
.long_name = NULL_IF_CONFIG_SMALL("Matroska / WebM"),
@ -3464,4 +3486,5 @@ AVInputFormat ff_webm_dash_manifest_demuxer = {
.read_header = webm_dash_manifest_read_header,
.read_packet = webm_dash_manifest_read_packet,
.read_close = matroska_read_close,
.priv_class = &webm_dash_class,
};