#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 |
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Comment (by Kamedo2):
I changed aaccoder.c line 806 from
{{{
? (refbits * 1.6f * avctx->sample_rate / 1024)
}}}
to
{{{
? (refbits * 2.4f * avctx->sample_rate / 1024)
}}}
This is certainly better, although exact optimal value is debatable.
I encoded 2 days of diverse sounds with many settings, and listened to 2
hours of the sounds. This encoder do a relatively good job even in abr
96kbps. It's not a blind test, but I feel the improvement. Also, I
compared abr 128kbps vs vbr -q 0.3, but still, abr is better. The vbr
exposes its weak point in relatively quiet, tonal sections. Low S/N and
stronger LPF effect.
[[Image(http://i40.tinypic.com/r1l7j4.png)]]
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Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2686#comment:160>
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