On Tue, Sep 29, 2009 at 3:51 PM, jacob jacob <[email protected]> wrote:
> I have two questions
>
>
> 2) ffmpeg does not multiply sample rate of lc aac sbr, so final file
> plays in slow motion (22050 instead of 44100). ( note: faad itself
> perfectly converts and multiplys it by just itself out of ffmpeg ).
> How to solve this problem for ffmpeg?
>
I hacked ffmpeg as following :
@ libavformat/utils.c
Index: utils.c
===================================================================
--- utils.c (revision 83)
+++ utils.c (working copy)
@@ -1896,6 +1896,12 @@
enc->codec_id == CODEC_ID_AAC ||
enc->codec_id == CODEC_ID_SPEEX))
return 0;
+ /* MUST decode some frames to fix SBR upsampling or
downsampling issue */
+ if(enc->codec_id == CODEC_ID_AAC && enc->sample_rate && !enc-
>codec){
+ enc->sample_rate = 0;
+ enc->channels = 0;
+ return 0;
+ }
break;
case CODEC_TYPE_VIDEO:
val = enc->width && enc->pix_fmt != PIX_FMT_NONE;
//@ libavcodec/aac_ac3_parser.c
Index: aac_ac3_parser.c
===================================================================
--- aac_ac3_parser.c (revision 83)
+++ aac_ac3_parser.c (working copy)
@@ -71,7 +71,12 @@
*poutbuf_size = buf_size;
/* update codec info */
- avctx->sample_rate = s->sample_rate;
+ /* we do not override AAC sample_rate because SBR+PS issue */
+ if(avctx->codec_id == CODEC_ID_AAC){
+ if(!avctx->sample_rate)
+ avctx->sample_rate = s->sample_rate;
+ }else
+ avctx->sample_rate = s->sample_rate;
if(s->codec_id)
avctx->codec_id = s->codec_id;
@@ -84,7 +89,12 @@
avctx->codec_id == CODEC_ID_EAC3)))) {
avctx->channels = avctx->request_channels;
} else if (avctx->codec_id != CODEC_ID_AAC || s->channels) {
- avctx->channels = s->channels;
+ /* we do not override AAC channels because SBR+PS issue */
+ if(avctx->codec_id == CODEC_ID_AAC){
+ if(!avctx->channels)
+ avctx->channels = s->channels;
+ }else
+ avctx->channels = s->channels;
avctx->channel_layout = s->channel_layout;
}
avctx->bit_rate = s->bit_rate;
--
-----------------------------------------------------------------------------------------
My key fingerprint: d1:03:f5:32:26:ff:d7:3c:e4:42:e3:51:ec:92:78:b2
Inspired by http://www.nextplayer.net. Your potential. Our passion.
_______________________________________________
libav-user mailing list
[email protected]
https://lists.mplayerhq.hu/mailman/listinfo/libav-user
