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aacdec: Rework channel mapping compatibility hacks.

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For a PCE based configuration map the channels solely based on tags.
For an indexed configuration map the channels solely based on position.

This works with all known exotic samples including al17, elem_id0, bad_concat,
and lfe_is_sce.

Originally committed as revision 25098 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Alex Converse 2010-09-10 18:01:48 +00:00
parent 11198b18db
commit bb2d8e9f05
2 changed files with 4 additions and 24 deletions
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1
libavcodec/aac.h
View File

@ -251,7 +251,6 @@ typedef struct {
*/
ChannelElement *che[4][MAX_ELEM_ID];
ChannelElement *tag_che_map[4][MAX_ELEM_ID];
uint8_t tags_seen_this_frame[4][MAX_ELEM_ID];
int tags_mapped;
/** @} */

27
libavcodec/aacdec.c
View File

@ -113,28 +113,11 @@ static const char overread_err[] = "Input buffer exhausted before END element fo
static ChannelElement *get_che(AACContext *ac, int type, int elem_id)
{
/* Some buggy encoders appear to set all elem_ids to zero and rely on
channels always occurring in the same order. This is expressly forbidden
by the spec but we will try to work around it.
*/
int err_printed = 0;
while (ac->tags_seen_this_frame[type][elem_id] && elem_id < MAX_ELEM_ID) {
if (ac->output_configured < OC_LOCKED && !err_printed) {
av_log(ac->avctx, AV_LOG_WARNING, "Duplicate channel tag found, attempting to remap.\n");
err_printed = 1;
}
elem_id++;
}
if (elem_id == MAX_ELEM_ID)
return NULL;
ac->tags_seen_this_frame[type][elem_id] = 1;
if (ac->tag_che_map[type][elem_id]) {
// For PCE based channel configurations map the channels solely based on tags.
if (!ac->m4ac.chan_config) {
return ac->tag_che_map[type][elem_id];
}
if (ac->tags_mapped >= tags_per_config[ac->m4ac.chan_config]) {
return NULL;
}
// For indexed channel configurations map the channels solely based on position.
switch (ac->m4ac.chan_config) {
case 7:
if (ac->tags_mapped == 3 && type == TYPE_CPE) {
@ -242,7 +225,6 @@ static av_cold int output_configure(AACContext *ac,
}
memset(ac->tag_che_map, 0, 4 * MAX_ELEM_ID * sizeof(ac->che[0][0]));
ac->tags_mapped = 0;
avctx->channel_layout = aac_channel_layout[channel_config - 1];
} else {
@ -263,7 +245,6 @@ static av_cold int output_configure(AACContext *ac,
}
memcpy(ac->tag_che_map, ac->che, 4 * MAX_ELEM_ID * sizeof(ac->che[0][0]));
ac->tags_mapped = 4 * MAX_ELEM_ID;
avctx->channel_layout = 0;
}
@ -1964,7 +1945,7 @@ static int aac_decode_frame(AVCodecContext *avctx, void *data,
}
}
memset(ac->tags_seen_this_frame, 0, sizeof(ac->tags_seen_this_frame));
ac->tags_mapped = 0;
// parse
while ((elem_type = get_bits(&gb, 3)) != TYPE_END) {
elem_id = get_bits(&gb, 4);