From ca1fa4144fbde99a88589c4b02648980b7d4c2d8 Mon Sep 17 00:00:00 2001 From: Alex Converse Date: Thu, 4 Mar 2010 02:30:51 +0000 Subject: AAC parser: Don't write channels, sample rate, and frame size each frame. Thanks to backwards compatible HE-AAC signalling these values are unreliable. Originally committed as revision 22194 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/aac_ac3_parser.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) (limited to 'libavcodec/aac_ac3_parser.c') diff --git a/libavcodec/aac_ac3_parser.c b/libavcodec/aac_ac3_parser.c index 85993c09b7..83ad9c56f9 100644 --- a/libavcodec/aac_ac3_parser.c +++ b/libavcodec/aac_ac3_parser.c @@ -71,10 +71,16 @@ get_next: *poutbuf_size = buf_size; /* update codec info */ - avctx->sample_rate = s->sample_rate; if(s->codec_id) avctx->codec_id = s->codec_id; + /* Due to backwards compatible HE-AAC the sample rate, channel count, + and total number of samples found in an AAC ADTS header are not + reliable. Bit rate is still accurate because the total frame duration in + seconds is still correct (as is the number of bits in the frame). */ + if (avctx->codec_id != CODEC_ID_AAC) { + avctx->sample_rate = s->sample_rate; + /* allow downmixing to stereo (or mono for AC-3) */ if(avctx->request_channels > 0 && avctx->request_channels < s->channels && @@ -83,12 +89,14 @@ get_next: (avctx->codec_id == CODEC_ID_AC3 || avctx->codec_id == CODEC_ID_EAC3)))) { avctx->channels = avctx->request_channels; - } else if (avctx->codec_id != CODEC_ID_AAC || s->channels) { + } else { avctx->channels = s->channels; avctx->channel_layout = s->channel_layout; } - avctx->bit_rate = s->bit_rate; avctx->frame_size = s->samples; + } + + avctx->bit_rate = s->bit_rate; return i; } -- cgit v1.2.3