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mov: support random access point grouping

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Frames described by this grouping are the starter of a closed or
an open GOP.
This is useful for open GOP of H.264 stream which is not described
by sync sample atom.

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
This commit is contained in:
Yusuke Nakamura 2012-04-24 08:51:29 +09:00 committed by Luca Barbato
parent 7d8431004a
commit d17d0ec8c2
2 changed files with 60 additions and 0 deletions
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7
libavformat/isom.h
View File

@ -87,6 +87,11 @@ typedef struct {
unsigned flags;
} MOVTrackExt;
typedef struct {
unsigned int count;
unsigned int index;
} MOVSbgp;
typedef struct MOVStreamContext {
AVIOContext *pb;
int ffindex; ///< AVStream index
@ -128,6 +133,8 @@ typedef struct MOVStreamContext {
int has_palette;
int64_t data_size;
int64_t track_end; ///< used for dts generation in fragmented movie files
unsigned int rap_group_count;
MOVSbgp *rap_group;
} MOVStreamContext;
typedef struct MOVContext {

53
libavformat/mov.c
View File

@ -1736,6 +1736,46 @@ static int mov_read_ctts(MOVContext *c, AVIOContext *pb, MOVAtom atom)
return 0;
}
static int mov_read_sbgp(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
AVStream *st;
MOVStreamContext *sc;
unsigned int i, entries;
uint8_t version;
uint32_t grouping_type;
if (c->fc->nb_streams < 1)
return 0;
st = c->fc->streams[c->fc->nb_streams-1];
sc = st->priv_data;
version = avio_r8(pb); /* version */
avio_rb24(pb); /* flags */
grouping_type = avio_rl32(pb);
if (grouping_type != MKTAG( 'r','a','p',' '))
return 0; /* only support 'rap ' grouping */
if (version == 1)
avio_rb32(pb); /* grouping_type_parameter */
entries = avio_rb32(pb);
if (!entries)
return 0;
if (entries >= UINT_MAX / sizeof(*sc->rap_group))
return AVERROR_INVALIDDATA;
sc->rap_group = av_malloc(entries * sizeof(*sc->rap_group));
if (!sc->rap_group)
return AVERROR(ENOMEM);
for (i = 0; i < entries && !pb->eof_reached; i++) {
sc->rap_group[i].count = avio_rb32(pb); /* sample_count */
sc->rap_group[i].index = avio_rb32(pb); /* group_description_index */
}
sc->rap_group_count = i;
return pb->eof_reached ? AVERROR_EOF : 0;
}
static void mov_build_index(MOVContext *mov, AVStream *st)
{
MOVStreamContext *sc = st->priv_data;
@ -1770,6 +1810,9 @@ static void mov_build_index(MOVContext *mov, AVStream *st)
unsigned int stts_sample = 0;
unsigned int sample_size;
unsigned int distance = 0;
unsigned int rap_group_index = 0;
unsigned int rap_group_sample = 0;
int rap_group_present = sc->rap_group_count && sc->rap_group;
int key_off = (sc->keyframes && sc->keyframes[0] > 0) || (sc->stps_data && sc->stps_data[0] > 0);
current_dts -= sc->dts_shift;
@ -1805,6 +1848,14 @@ static void mov_build_index(MOVContext *mov, AVStream *st)
if (stps_index + 1 < sc->stps_count)
stps_index++;
}
if (rap_group_present && rap_group_index < sc->rap_group_count) {
if (sc->rap_group[rap_group_index].index > 0)
keyframe = 1;
if (++rap_group_sample == sc->rap_group[rap_group_index].count) {
rap_group_sample = 0;
rap_group_index++;
}
}
if (keyframe)
distance = 0;
sample_size = sc->sample_size > 0 ? sc->sample_size : sc->sample_sizes[current_sample];
@ -2054,6 +2105,7 @@ static int mov_read_trak(MOVContext *c, AVIOContext *pb, MOVAtom atom)
av_freep(&sc->keyframes);
av_freep(&sc->stts_data);
av_freep(&sc->stps_data);
av_freep(&sc->rap_group);
return 0;
}
@ -2497,6 +2549,7 @@ static const MOVParseTableEntry mov_default_parse_table[] = {
{ MKTAG('c','m','o','v'), mov_read_cmov },
{ MKTAG('c','h','a','n'), mov_read_chan }, /* channel layout */
{ MKTAG('d','v','c','1'), mov_read_dvc1 },
{ MKTAG('s','b','g','p'), mov_read_sbgp },
{ 0, NULL }
};