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avformat/mxfdec: compute both essence_offset and essence_length in mxf_compute_essence_containers

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Also compute the correct essence_offset and essence_length for all clip wrapped
essences.

Signed-off-by: Marton Balint <cus@passwd.hu>
pull/288/head
Marton Balint 7 years ago
parent 459282389c
commit 6345770eeb
1 changed files with 57 additions and 51 deletions
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  1. 108
      libavformat/mxfdec.c

108
libavformat/mxfdec.c
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@ -98,6 +98,7 @@ typedef struct MXFPartition {
int pack_length;
int64_t pack_ofs; ///< absolute offset of pack in file, including run-in
int64_t body_offset;
KLVPacket first_essence_klv;
} MXFPartition;
typedef struct MXFCryptoContext {
@ -2784,47 +2785,76 @@ static int mxf_parse_handle_partition_or_eof(MXFContext *mxf)
return mxf->parsing_backward ? mxf_seek_to_previous_partition(mxf) : 1;
}
static int64_t round_to_kag(int64_t position, int kag_size)
{
/* TODO: account for run-in? the spec isn't clear whether KAG should account for it */
/* NOTE: kag_size may be any integer between 1 - 2^10 */
int64_t ret = (position / kag_size) * kag_size;
return ret == position ? ret : ret + kag_size;
}
static MXFWrappingScheme mxf_get_wrapping_by_body_sid(AVFormatContext *s, int body_sid)
{
for (int i = 0; i < s->nb_streams; i++) {
MXFTrack *track = s->streams[i]->priv_data;
if (track && track->body_sid == body_sid && track->wrapping != UnknownWrapped)
return track->wrapping;
}
return UnknownWrapped;
}
/**
* Figures out the proper offset and length of the essence container in each partition
*/
static void mxf_compute_essence_containers(MXFContext *mxf)
static void mxf_compute_essence_containers(AVFormatContext *s)
{
MXFContext *mxf = s->priv_data;
int x;
/* everything is already correct */
if (mxf->op == OPAtom)
return;
for (x = 0; x < mxf->partitions_count; x++) {
MXFPartition *p = &mxf->partitions[x];
MXFWrappingScheme wrapping;
if (!p->body_sid)
continue; /* BodySID == 0 -> no essence */
if (x >= mxf->partitions_count - 1)
break; /* FooterPartition - can't compute length (and we don't need to) */
/* for non clip-wrapped essences we compute essence_offset
* for clip wrapped essences we point essence_offset after the KL (usually klv.offset + 20 or 25)
*/
/* essence container spans to the next partition */
p->essence_length = mxf->partitions[x+1].this_partition - p->essence_offset;
wrapping = (mxf->op == OPAtom) ? ClipWrapped : mxf_get_wrapping_by_body_sid(s, p->body_sid);
if (p->essence_length < 0) {
/* next ThisPartition < essence_offset */
p->essence_length = 0;
av_log(mxf->fc, AV_LOG_ERROR,
"partition %i: bad ThisPartition = %"PRIX64"\n",
x+1, mxf->partitions[x+1].this_partition);
if (wrapping == ClipWrapped) {
p->essence_offset = p->first_essence_klv.next_klv - p->first_essence_klv.length;
p->essence_length = p->first_essence_klv.length;
} else {
int64_t op1a_essence_offset =
p->this_partition +
round_to_kag(p->pack_length, p->kag_size) +
round_to_kag(p->header_byte_count, p->kag_size) +
round_to_kag(p->index_byte_count, p->kag_size);
/* NOTE: op1a_essence_offset may be less than to klv.offset (C0023S01.mxf) */
if (IS_KLV_KEY(p->first_essence_klv.key, mxf_system_item_key_cp) || IS_KLV_KEY(p->first_essence_klv.key, mxf_system_item_key_gc))
p->essence_offset = p->first_essence_klv.offset;
else
p->essence_offset = op1a_essence_offset;
/* essence container spans to the next partition */
if (x < mxf->partitions_count - 1)
p->essence_length = mxf->partitions[x+1].this_partition - p->essence_offset;
if (p->essence_length < 0) {
/* next ThisPartition < essence_offset */
p->essence_length = 0;
av_log(mxf->fc, AV_LOG_ERROR,
"partition %i: bad ThisPartition = %"PRIX64"\n",
x+1, mxf->partitions[x+1].this_partition);
}
}
}
}
static int64_t round_to_kag(int64_t position, int kag_size)
{
/* TODO: account for run-in? the spec isn't clear whether KAG should account for it */
/* NOTE: kag_size may be any integer between 1 - 2^10 */
int64_t ret = (position / kag_size) * kag_size;
return ret == position ? ret : ret + kag_size;
}
static int is_pcm(enum AVCodecID codec_id)
{
/* we only care about "normal" PCM codecs until we get samples */
@ -3036,32 +3066,8 @@ static int mxf_read_header(AVFormatContext *s)
return AVERROR_INVALIDDATA;
}
if (!mxf->current_partition->essence_offset) {
/* for OP1a we compute essence_offset
* for OPAtom we point essence_offset after the KL (usually op1a_essence_offset + 20 or 25)
* TODO: for OP1a we could eliminate this entire if statement, always stopping parsing at op1a_essence_offset
* for OPAtom we still need the actual essence_offset though (the KL's length can vary)
*/
int64_t op1a_essence_offset =
mxf->current_partition->this_partition +
round_to_kag(mxf->current_partition->pack_length, mxf->current_partition->kag_size) +
round_to_kag(mxf->current_partition->header_byte_count, mxf->current_partition->kag_size) +
round_to_kag(mxf->current_partition->index_byte_count, mxf->current_partition->kag_size);
if (mxf->op == OPAtom) {
/* point essence_offset to the actual data
* OPAtom has all the essence in one big KLV
*/
mxf->current_partition->essence_offset = avio_tell(s->pb);
mxf->current_partition->essence_length = klv.length;
} else {
/* NOTE: op1a_essence_offset may be less than to klv.offset (C0023S01.mxf) */
if (IS_KLV_KEY(klv.key, mxf_system_item_key_cp) || IS_KLV_KEY(klv.key, mxf_system_item_key_gc))
mxf->current_partition->essence_offset = klv.offset;
else
mxf->current_partition->essence_offset = op1a_essence_offset;
}
}
if (!mxf->current_partition->first_essence_klv.offset)
mxf->current_partition->first_essence_klv = klv;
if (!essence_offset)
essence_offset = klv.offset;
@ -3100,8 +3106,6 @@ static int mxf_read_header(AVFormatContext *s)
}
avio_seek(s->pb, essence_offset, SEEK_SET);
mxf_compute_essence_containers(mxf);
/* we need to do this before computing the index tables
* to be able to fill in zero IndexDurations with st->duration */
if ((ret = mxf_parse_structural_metadata(mxf)) < 0)
@ -3123,6 +3127,8 @@ static int mxf_read_header(AVFormatContext *s)
goto fail;
}
mxf_compute_essence_containers(s);
mxf_handle_small_eubc(s);
return 0;

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