[FFmpeg-trac] #2686(avcodec:open): Native AAC encoder collapses at high bitrates on some samples
FFmpeg
trac at avcodec.org
Wed Jul 17 21:57:37 CEST 2013
#2686: Native AAC encoder collapses at high bitrates on some samples
-------------------------------------+-------------------------------------
Reporter: Kamedo2 | Owner:
Type: defect | Status: open
Priority: normal | Component: avcodec
Version: git-master | Resolution:
Keywords: aac | Blocked By:
regression | Reproduced by developer: 1
Blocking: |
Analyzed by developer: 0 |
-------------------------------------+-------------------------------------
Comment (by Kamedo2):
from line 300:
{{{
const int chan_bitrate = ctx->avctx->bit_rate / ((ctx->avctx->flags &
CODEC_FLAG_QSCALE) ? 2.0f : ctx->avctx->channels);
}}}
to:
{{{
const int chan_bitrate = FFMIN(ctx->avctx->bit_rate, 240000) /
((ctx->avctx->flags & CODEC_FLAG_QSCALE) ? 2.0 : ctx->avctx->channels);
}}}
significantly improves the quality. Bitrates remain relatively high in
this change.
I have not tested all cases, but it works on 256kbps, 320kbps, and 384kbps
on many sounds.
--
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2686#comment:41>
FFmpeg <http://ffmpeg.org>
FFmpeg issue tracker
More information about the FFmpeg-trac
mailing list