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[FFmpeg-devel,4/4] aac_latm: Align inband PCE to the start of the payload

Message ID 20170209174039.8218-4-alex.converse@gmail.com
State Accepted
Commit 1fce67d6403a4540181f6ed05abf5b3edd4ef014
Headers show

Commit Message

Alex Converse Feb. 9, 2017, 5:40 p.m. UTC 
A strict reading of the spec seems to imply that it should be aligned to
the start of the element instance tag, but that would break all of the
samples with PCEs.

It seems like a well formed LATM stream should have its PCE in the ASC
rather than inband.

Fixes ticket 4544
---
 libavcodec/aacdec_template.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
diff mbox

Patch

diff --git a/libavcodec/aacdec_template.c b/libavcodec/aacdec_template.c
index 6654416e69..1f14a1cbae 100644
--- a/libavcodec/aacdec_template.c
+++ b/libavcodec/aacdec_template.c
@@ -2949,6 +2949,7 @@  static int aac_decode_frame_int(AVCodecContext *avctx, void *data,
     int err, elem_id;
     int samples = 0, multiplier, audio_found = 0, pce_found = 0;
     int is_dmono, sce_count = 0;
+    int payload_alignment;
 
     ac->frame = data;
 
@@ -2971,6 +2972,7 @@  static int aac_decode_frame_int(AVCodecContext *avctx, void *data,
     // This may lead to an undefined profile being signaled
     ac->avctx->profile = ac->oc[1].m4ac.object_type - 1;
 
+    payload_alignment = get_bits_count(gb);
     ac->tags_mapped = 0;
     // parse
     while ((elem_type = get_bits(gb, 3)) != TYPE_END) {
@@ -3025,7 +3027,8 @@  static int aac_decode_frame_int(AVCodecContext *avctx, void *data,
             uint8_t layout_map[MAX_ELEM_ID*4][3];
             int tags;
             push_output_configuration(ac);
-            tags = decode_pce(avctx, &ac->oc[1].m4ac, layout_map, gb, 0);
+            tags = decode_pce(avctx, &ac->oc[1].m4ac, layout_map, gb,
+                              payload_alignment);
             if (tags < 0) {
                 err = tags;
                 break;