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avformat/mxfdec: make edit_units_per_packet a track property

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Signed-off-by: Marton Balint <cus@passwd.hu>
This commit is contained in:
Marton Balint 2018-05-24 10:30:12 +02:00
parent f217be2cb8
commit ae64c68208
1 changed files with 26 additions and 25 deletions
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51
libavformat/mxfdec.c
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@ -173,6 +173,7 @@ typedef struct {
int index_sid;
int body_sid;
MXFWrappingScheme wrapping;
int edit_units_per_packet; /* how many edit units to read at a time (PCM, ClipWrapped) */
} MXFTrack;
typedef struct MXFDescriptor {
@ -286,7 +287,6 @@ typedef struct MXFContext {
int64_t current_edit_unit;
int nb_index_tables;
MXFIndexTable *index_tables;
int edit_units_per_packet; ///< how many edit units to read at a time (PCM, OPAtom)
} MXFContext;
/* NOTE: klv_offset is not set (-1) for local keys */
@ -2858,36 +2858,46 @@ static AVStream* mxf_get_opatom_stream(MXFContext *mxf)
return NULL;
}
static MXFIndexTable *mxf_find_index_table(MXFContext *mxf, int index_sid)
{
int i;
for (i = 0; i < mxf->nb_index_tables; i++)
if (mxf->index_tables[i].index_sid == index_sid)
return &mxf->index_tables[i];
return NULL;
}
/**
* Deal with the case where for some audio atoms EditUnitByteCount is
* very small (2, 4..). In those cases we should read more than one
* sample per call to mxf_read_packet().
*/
static void mxf_handle_small_eubc(AVFormatContext *s)
static void mxf_compute_edit_units_per_packet(MXFContext *mxf, AVStream *st)
{
MXFContext *mxf = s->priv_data;
MXFTrack *track;
MXFTrack *track = st->priv_data;
MXFIndexTable *t;
/* assuming non-OPAtom == frame wrapped
* no sane writer would wrap 2 byte PCM packets with 20 byte headers.. */
AVStream *st = mxf_get_opatom_stream(mxf);
if (!st)
if (!track)
return;
track->edit_units_per_packet = 1;
if (track->wrapping != ClipWrapped)
return;
t = mxf_find_index_table(mxf, track->index_sid);
/* expect PCM with exactly one index table segment and a small (< 32) EUBC */
if (st->codecpar->codec_type != AVMEDIA_TYPE_AUDIO ||
!is_pcm(st->codecpar->codec_id) ||
mxf->nb_index_tables != 1 ||
mxf->index_tables[0].nb_segments != 1 ||
mxf->index_tables[0].segments[0]->edit_unit_byte_count >= 32)
!t ||
t->nb_segments != 1 ||
t->segments[0]->edit_unit_byte_count >= 32)
return;
/* arbitrarily default to 48 kHz PAL audio frame size */
/* TODO: We could compute this from the ratio between the audio
* and video edit rates for 48 kHz NTSC we could use the
* 1802-1802-1802-1802-1801 pattern. */
track = st->priv_data;
mxf->edit_units_per_packet = FFMAX(1, track->edit_rate.num / track->edit_rate.den / 25);
track->edit_units_per_packet = FFMAX(1, track->edit_rate.num / track->edit_rate.den / 25);
}
/**
@ -3012,7 +3022,6 @@ static int mxf_read_header(AVFormatContext *s)
int ret;
mxf->last_forward_tell = INT64_MAX;
mxf->edit_units_per_packet = 1;
if (!mxf_read_sync(s->pb, mxf_header_partition_pack_key, 14)) {
av_log(s, AV_LOG_ERROR, "could not find header partition pack key\n");
@ -3112,7 +3121,8 @@ static int mxf_read_header(AVFormatContext *s)
mxf_compute_essence_containers(s);
mxf_handle_small_eubc(s);
for (int i = 0; i < s->nb_streams; i++)
mxf_compute_edit_units_per_packet(mxf, s->streams[i]);
return 0;
fail:
@ -3121,15 +3131,6 @@ fail:
return ret;
}
static MXFIndexTable *mxf_find_index_table(MXFContext *mxf, int index_sid)
{
int i;
for (i = 0; i < mxf->nb_index_tables; i++)
if (mxf->index_tables[i].index_sid == index_sid)
return &mxf->index_tables[i];
return NULL;
}
/* Get the edit unit of the next packet from current_offset in a track. The returned edit unit can be original_duration as well! */
static int mxf_get_next_track_edit_unit(MXFContext *mxf, MXFTrack *track, int64_t current_offset, int64_t *edit_unit_out)
{
@ -3391,7 +3392,7 @@ static int mxf_read_packet(AVFormatContext *s, AVPacket *pkt)
if (mxf->current_edit_unit >= track->original_duration)
return AVERROR_EOF;
edit_units = FFMIN(mxf->edit_units_per_packet, track->original_duration - mxf->current_edit_unit);
edit_units = FFMIN(track->edit_units_per_packet, track->original_duration - mxf->current_edit_unit);
if ((ret = mxf_edit_unit_absolute_offset(mxf, t, mxf->current_edit_unit, NULL, &pos, 1)) < 0)
return ret;