Using Aften:
ffmpeg -threads 4 -v -10 -y -i "test.mp3" -acodec pcm_s16le -f u16le - | sox --temp "D:\Encoding Temp" -t raw -e signed-integer -2 -c2 -r48000 - -t wav - norm remix - | aften -v 2 -b 128 - "test.ac3"
Mediainfo reports the resulting ac3 file correctly as mono.
Using OggEnc:
ffmpeg -threads 4 -v -10 -y -i "test.mp3" -acodec pcm_s16le -f u16le - | sox --temp "D:\Encoding Temp" -t raw -e signed-integer -2 -c2 -r48000 - -t wav - norm remix - | oggenc --quiet -r -b 128 -C 1 -R 48000 --ignorelength --utf8 -o "test.ogg" -
Mediainfo reports the resulting ogg file correctly as mono.
Using NeroAacEnc:
ffmpeg -threads 4 -v -10 -y -i "test.mp3" -acodec pcm_s16le -f u16le - | sox --temp "D:\Encoding Temp" -t raw -e signed-integer -2 -c2 -r48000 - -t wav - norm remix - | neroAacEnc -if - -br 128000 -lc -ignorelength -of "test.aac"
Mediainfo reports the resulting aac file as stereo, where as Quicktime reports it correctly as mono.
To produce this test I used:
- MediaInfo Command line, MediaInfoLib - v0.7.32
- FFmpeg version SVN-r22960, Copyright (c) 2000-2010 the FFmpeg developers built on Apr 25 2010 07:22:06 with gcc 4.4.2
configuration: --enable-memalign-hack --cross-prefix=i686-mingw32- --cc=ccache-i686-mingw32-gcc --arch=i686 --target-os=mingw32 --enable-runtime-cpudetect --enable-avisynth --enable-gpl --enable-version3 --enable-bzlib --enable-libgsm --enable-libfaad --enable-pthreads --enable-libvorbis --enable-libtheora --enable-libspeex --enable-libmp3lame --enable-libopenjpeg --enable-libxvid --enable-libschroedinger --enable-libx264 --enable-libopencore_amrwb --enable-libopencore_amrn
- OggEnc v2.87 (libvorbis 1.3.1)
- aften svn r703
I also checked: current mplayer and ffmpeg also identify the aac file as mono.
Since all the files besides the .aac file are detected correctly the problem does not rest with the method and since quicktime, mplayer and ffmpeg all detect the file as mono I suspect the problem lies with mediainfo.
I uploaded the .mp3, .ac3, .ogg and .aac file to: http://stashbox.org/895434/should%20be%20detected%20as%20mono.zip
Hope this helps to track&fix the problem.
Cu Selur
I can confrm this bug. I have mono file as ffmpeg reports but MI reports stereo
The file can not be downloaded.
I have difficulties with HE-ACC(v1 or v2), because I don't parse the complete AAC bitstream, and PS presence info is not always set, so I must do some guess, and sometimes my guess is wrong..
Integration of a more complete AAC decoder is planned, but I don't know when I will have the time to do it. When this integration is done, I remember the code for guessing if it is mono or stereo (without PS or with PS)
Sounds like the issue has been diagnosed. My sample may be found here: http://207.46.245.46/Video/iPad/WiFi/a_tdy_witt_car_100908.mov. Related may be a bug where the sample rate is actually 22,050 but MI 7.35 indicates 44.1KHz. Files are encoded with Telestream Flipfactory.
jkcrum, I think this is same issue. and correction is still long to implement (current guess is better because there are more files qicth HE-AAC v1/v2 than mono files)