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mxfdec: Compute packet offsets properly. 

This replaces the old essence_offset code.

Signed-off-by: Janne Grunau <janne-libav@jannau.net>
This commit is contained in:
Tomas Härdin 2011-12-08 12:23:36 +01:00 committed by Janne Grunau
parent f4187945a0
commit 3cb33fbe91
1 changed files with 37 additions and 16 deletions
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53
libavformat/mxfdec.c
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@ -190,9 +190,6 @@ typedef struct {
uint8_t *local_tags;
int local_tags_count;
uint64_t footer_partition;
int64_t essence_offset;
int first_essence_kl_length;
int64_t first_essence_length;
KLVPacket current_klv_data;
int current_klv_index;
int run_in;
@ -1023,6 +1020,34 @@ static int mxf_get_sorted_table_segments(MXFContext *mxf, int *nb_sorted_segment
return 0;
}
/**
* Computes the absolute file offset of the given essence container offset
*/
static int mxf_absolute_bodysid_offset(MXFContext *mxf, int body_sid, int64_t offset, int64_t *offset_out)
{
int x;
int64_t offset_in = offset; /* for logging */
for (x = 0; x < mxf->partitions_count; x++) {
MXFPartition *p = &mxf->partitions[x];
if (p->body_sid != body_sid)
continue;
if (offset < p->essence_length || !p->essence_length) {
*offset_out = p->essence_offset + offset;
return 0;
}
offset -= p->essence_length;
}
av_log(mxf->fc, AV_LOG_ERROR, "failed to find absolute offset of %lx in BodySID %i - partial file?\n",
offset_in, body_sid);
return AVERROR_INVALIDDATA;
}
static int mxf_parse_index(MXFContext *mxf, int track_id, AVStream *st)
{
int64_t accumulated_offset = 0;
@ -1109,10 +1134,10 @@ static int mxf_parse_index(MXFContext *mxf, int track_id, AVStream *st)
flags = AVINDEX_KEYFRAME;
}
if (k > 0 && pos < mxf->first_essence_length && accumulated_offset == 0)
pos += mxf->first_essence_kl_length;
pos += mxf->essence_offset;
if (mxf_absolute_bodysid_offset(mxf, tableseg->body_sid, pos, &pos) < 0) {
/* probably partial file - no point going further for this stream */
break;
}
av_dlog(mxf->fc, "Stream %d IndexEntry %d TrackID %d Offset %"PRIx64" Timestamp %"PRId64"\n",
st->index, st->nb_index_entries, track_id, pos, sample_duration * st->nb_index_entries);
@ -1546,6 +1571,7 @@ static int mxf_read_header(AVFormatContext *s, AVFormatParameters *ap)
{
MXFContext *mxf = s->priv_data;
KLVPacket klv;
int64_t essence_offset = 0;
mxf->last_forward_tell = INT64_MAX;
@ -1577,13 +1603,8 @@ static int mxf_read_header(AVFormatContext *s, AVFormatParameters *ap)
compute_partition_essence_offset(s, mxf, &klv);
}
if (!mxf->essence_offset)
mxf->essence_offset = klv.offset;
if (!mxf->first_essence_kl_length && IS_KLV_KEY(klv.key, mxf_essence_element_key)) {
mxf->first_essence_kl_length = avio_tell(s->pb) - klv.offset;
mxf->first_essence_length = klv.length;
}
if (!essence_offset)
essence_offset = klv.offset;
/* seek to footer, previous partition or stop */
if (mxf_parse_handle_essence(mxf) <= 0)
@ -1617,11 +1638,11 @@ static int mxf_read_header(AVFormatContext *s, AVFormatParameters *ap)
avio_skip(s->pb, klv.length);
}
/* FIXME avoid seek */
if (!mxf->essence_offset) {
if (!essence_offset) {
av_log(s, AV_LOG_ERROR, "no essence\n");
return AVERROR_INVALIDDATA;
}
avio_seek(s->pb, mxf->essence_offset, SEEK_SET);
avio_seek(s->pb, essence_offset, SEEK_SET);
mxf_compute_essence_containers(mxf);