[FFmpeg-trac] #2686(avcodec:open): Native AAC encoder collapses at high bitrates on some samples
FFmpeg
trac at avcodec.org
Sun Jun 30 17:26:18 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):
I successfully applied the patch. klaussfreire's repository is in here.
http://ffmpeg.org/pipermail/ffmpeg-devel/2013-May/143216.html
Or, you can use https://dl.dropboxusercontent.com/u/81238453/aac.patch
(Thank you Takuan @K4095) to patch from current git head.
However, still, it has a distinctive bug. The sound disappears partially
when the sound is white noise-like.
The bug #2706 was that the sound warbles when the sound was a sine wave.
That was solved by this patch, but this creates new problem.
{{{
ffmpeg54292 -v 9 -loglevel
99 -filter_complex "aevalsrc=-0.5+random(0)" -c:a aac -strict experimental
-ar 4
4100 -ac 2 -b:a 256k -t 4 "C:\Users\PCC\Documents\ABC-
HR\whitenoise_256k.mp4"
ffmpeg version N-54292-g97947d9 Copyright (c) 2000-2013 the FFmpeg
developers
built on Jun 30 2013 20:34:13 with gcc 4.8.1 (GCC)
configuration: --enable-gpl --enable-version3 --enable-nonfree --enable-
libfdk
-aac --extra-ldflags=-static --extra-cflags='-march=nocona -mfpmath=sse'
--optfl
ags=-O2
libavutil 52. 38.100 / 52. 38.100
libavcodec 55. 18.100 / 55. 18.100
libavformat 55. 10.100 / 55. 10.100
libavdevice 55. 2.100 / 55. 2.100
libavfilter 3. 77.101 / 3. 77.101
libswscale 2. 3.100 / 2. 3.100
libswresample 0. 17.102 / 0. 17.102
libpostproc 52. 3.100 / 52. 3.100
Splitting the commandline.
Reading option '-v' ... matched as option 'v' (set logging level) with
argument
'9'.
Reading option '-loglevel' ... matched as option 'loglevel' (set logging
level)
with argument '99'.
Reading option '-filter_complex' ... matched as option 'filter_complex'
(create
a complex filtergraph) with argument 'aevalsrc=-0.5+random(0)'.
Reading option '-c:a' ... matched as option 'c' (codec name) with argument
'aac'
.
Reading option '-strict' ... matched as AVOption 'strict' with argument
'experim
ental'.
Reading option '-ar' ... matched as option 'ar' (set audio sampling rate
(in Hz)
) with argument '44100'.
Reading option '-ac' ... matched as option 'ac' (set number of audio
channels) w
ith argument '2'.
Reading option '-b:a' ... matched as option 'b' (video bitrate (please use
-b:v)
) with argument '256k'.
Reading option '-t' ... matched as option 't' (record or transcode
"duration" se
conds of audio/video) with argument '4'.
Reading option 'C:\Users\PCC\Documents\ABC-HR\whitenoise_256k.mp4' ...
matched a
s output file.
Finished splitting the commandline.
Parsing a group of options: global .
Applying option v (set logging level) with argument 9.
Applying option filter_complex (create a complex filtergraph) with
argument aeva
lsrc=-0.5+random(0).
Successfully parsed a group of options.
Parsing a group of options: output file C:\Users\PCC\Documents\ABC-
HR\whitenoise
_256k.mp4.
Applying option c:a (codec name) with argument aac.
Applying option ar (set audio sampling rate (in Hz)) with argument 44100.
Applying option ac (set number of audio channels) with argument 2.
Applying option b:a (video bitrate (please use -b:v)) with argument 256k.
Applying option t (record or transcode "duration" seconds of audio/video)
with a
rgument 4.
Successfully parsed a group of options.
Opening an output file: C:\Users\PCC\Documents\ABC-HR\whitenoise_256k.mp4.
detected 8 logical cores
[Parsed_aevalsrc_0 @ 0140bea0] compat: called with args=[-0.5+random(0)]
[Parsed_aevalsrc_0 @ 0140bea0] Setting 'exprs' to value '-0.5+random(0)'
[audio format for output stream 0:0 @ 01412880] Setting 'sample_fmts' to
value '
fltp'
[audio format for output stream 0:0 @ 01412880] Setting 'sample_rates' to
value
'44100'
[audio format for output stream 0:0 @ 01412880] Setting 'channel_layouts'
to val
ue '0x3'
Successfully opened the file.
[audio format for output stream 0:0 @ 01412880] auto-inserting filter
'auto-inse
rted resampler 0' between the filter 'Parsed_aevalsrc_0' and the filter
'audio f
ormat for output stream 0:0'
[AVFilterGraph @ 0039f3c0] query_formats: 3 queried, 6 merged, 3 already
done, 0
delayed
[Parsed_aevalsrc_0 @ 0140bea0] sample_rate:44100 chlayout:mono
duration:-1.00000
0
[auto-inserted resampler 0 @ 0039f2a0] [SWR @ 00393160] Using double
precision m
ode
0.707107
0.707107
[auto-inserted resampler 0 @ 0039f2a0] ch:1 chl:mono fmt:dblp r:44100Hz ->
ch:2
chl:stereo fmt:fltp r:44100Hz
Output #0, mp4, to 'C:\Users\PCC\Documents\ABC-HR\whitenoise_256k.mp4':
Metadata:
encoder : Lavf55.10.100
Stream #0:0, 0, 1/44100: Audio: aac ([64][0][0][0] / 0x0040), 44100
Hz, ster
eo, fltp, 256 kb/s
Stream mapping:
aevalsrc -> Stream #0:0 (aac)
Press [q] to stop, [?] for help
No more output streams to write to, finishing.
size= 141kB time=00:00:04.01 bitrate= 288.4kbits/s
video:0kB audio:140kB subtitle:0 global headers:0kB muxing overhead
1.001409%
0 frames successfully decoded, 0 decoding errors
[AVIOContext @ 0141b640] Statistics: 30 seeks, 197 writeouts
}}}
The output mp4 I'm going to post sounds nothing like white noise.
--
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2686#comment:11>
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