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faroit / stempeg

Python I/O for STEM audio files
https://faroit.github.io/stempeg
MIT License
96 stars 13 forks source link

Tests failing with wrong shapes #2

Closed jaidevd closed 6 years ago

jaidevd commented 6 years ago

Hi author(s),

I'm trying to run the tests included in this package, but the assert statements on the shapes of the stems are failing. The tests expect a shape of (5, 265216, 2) but the file has a shape of (5, 267264, 2).

Is this a bug or have the files been updated without updating the tests?

Thanks!

faroit commented 6 years ago

Hey. Thanks for the report.

No, the test vectors weren't changed.

On my machine and on Travis the tests succeed. What version of ffmpeg are you using on what OS?

jaidevd commented 6 years ago

Hi @faroit I'm using version 2.8.11 on Ubuntu 16.04. Specifically, this is the output of ffmpeg -version:

ffmpeg version 2.8.11-0ubuntu0.16.04.1 Copyright (c) 2000-2017 the FFmpeg developers
built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.4) 20160609
configuration: --prefix=/usr --extra-version=0ubuntu0.16.04.1 --build-suffix=-ffmpeg --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --cc=cc --cxx=g++ --enable-gpl --enable-shared --disable-stripping --disable-decoder=libopenjpeg --disable-decoder=libschroedinger --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librtmp --enable-libschroedinger --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzvbi --enable-openal --enable-opengl --enable-x11grab --enable-libdc1394 --enable-libiec61883 --enable-libzmq --enable-frei0r --enable-libx264 --enable-libopencv
libavutil      54. 31.100 / 54. 31.100
libavcodec     56. 60.100 / 56. 60.100
libavformat    56. 40.101 / 56. 40.101
libavdevice    56.  4.100 / 56.  4.100
libavfilter     5. 40.101 /  5. 40.101
libavresample   2.  1.  0 /  2.  1.  0
libswscale      3.  1.101 /  3.  1.101
libswresample   1.  2.101 /  1.  2.101
libpostproc    53.  3.100 / 53.  3.100
faroit commented 6 years ago

okay, I can now reproduce your issue on travis: https://travis-ci.org/faroit/stempeg/builds/326423503

Basically this means ffmpeg > 3 decode the file differently regarding the zeros padding. I don't know yet what would be the best solution. Either force users to upgrade ffmpeg extending zeros to the output from within python

faroit commented 6 years ago

Okay, I figures out the difference.

it is because the older version ships with a different aac decoder which pads 2048 samples of silence in the beginning whereas the newer versions do only append 1024 samples:

https://travis-ci.org/faroit/stempeg/jobs/326442731#L511

faroit commented 6 years ago

Okay I did not find a better solution than issue a UserWarning if the ffmpeg version < 3 and the duration in samples cannot be divided by 1024 when writing stems.

Sorry, but these codecs are a mess....