[FFmpeg-trac] #2484(avfilter:open): atempo - low accuracy
FFmpeg
trac at avcodec.org
Sun Apr 21 00:40:30 CEST 2013
#2484: atempo - low accuracy
------------------------------------+-------------------------------------
Reporter: bars | Owner: pkoshevoy
Type: defect | Status: open
Priority: normal | Component: avfilter
Version: git-master | Resolution:
Keywords: atempo | Blocked By:
Blocking: | Reproduced by developer: 1
Analyzed by developer: 0 |
------------------------------------+-------------------------------------
Changes (by pkoshevoy):
* owner: => pkoshevoy
Comment:
The error is much worse at lower sample rates (8000Hz) -- off by more than
52 seconds.
$ /Developer/x86_64/bin/ffmpeg -f lavfi -i
'aevalsrc=s=8000:c=mono:exprs=sin(0.5*2*PI*t)*sin(440*2*PI*t):d=24000' -af
atempo=23976/25000 -y /nfs/scratch/DataSets/Video/au/06h-40m-
23976to25000-v2.au
ffmpeg version N-52339-g0dd25e4 Copyright (c) 2000-2013 the FFmpeg
developers
built on Apr 20 2013 13:29:29 with llvm-gcc 4.2.1 (LLVM build
2336.11.00)
configuration: --prefix=/Developer/x86_64 --enable-swscale --enable-
avfilter --enable-libmp3lame --enable-libvorbis --enable-libopus --enable-
libtheora --enable-libschroedinger --enable-libopenjpeg --enable-
libmodplug --enable-libvpx --enable-libspeex --enable-shared --enable-
pthreads --enable-gpl --enable-version3 --enable-libopencore-amrnb
--enable-libopencore-amrwb --enable-postproc --enable-libx264 --enable-
libxvid --enable-yasm --enable-runtime-cpudetect --extra-
cflags=-I/opt/local/include --extra-ldflags='-headerpad_max_install_names
-L/opt/local/lib'
libavutil 52. 27.100 / 52. 27.100
libavcodec 55. 5.100 / 55. 5.100
libavformat 55. 3.100 / 55. 3.100
libavdevice 55. 0.100 / 55. 0.100
libavfilter 3. 58.100 / 3. 58.100
libswscale 2. 2.100 / 2. 2.100
libswresample 0. 17.102 / 0. 17.102
libpostproc 52. 3.100 / 52. 3.100
Input #0, lavfi, from
'aevalsrc=s=8000:c=mono:exprs=sin(0.5*2*PI*t)*sin(440*2*PI*t):d=24000':
Duration: N/A, start: 0.000000, bitrate: 512 kb/s
Stream #0:0: Audio: pcm_f64le, 8000 Hz, mono, dbl, 512 kb/s
Output #0, au, to '/nfs/scratch/DataSets/Video/au/06h-40m-
23976to25000-v2.au':
Metadata:
encoder : Lavf55.3.100
Stream #0:0: Audio: pcm_s16be ([3][0][0][0] / 0x0003), 8000 Hz, mono,
s16, 128 kb/s
Stream mapping:
Stream #0:0 -> #0:0 (pcm_f64le -> pcm_s16be)
Press [q] to stop, [?] for help
size= 391837kB time=06:57:57.54 bitrate= 128.0kbits/s
video:0kB audio:391837kB subtitle:0 global headers:0kB muxing overhead
0.000008%
--
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2484#comment:5>
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