Workaround for MKV/AC3-DTS transcoding
Posted: Fri Jul 12, 2019 1:54 am
The story is well known, but for those who are not aware, we summarize it.
The problem:
-When we play content through the Web interface, we depend on the browser's codec. Given that there is a multitude of codecs and containers, we opt for real-time transcoding of the content, to a format and codec that most browsers accept
-Due to licensing problems with AC3 / DTS, QNAP eliminated the support for these codecs a few years ago, and so lost the ability to transcode content with these codecs. MKV is not the problem, it is just a container, the problem is the codecs used in the audio part of the container, the same happens with MP4
Code: Select all
[/share/CACHEDEV1_DATA] # ffmpeg
ffmpeg version 3.3.6 Copyright (c) 2000-2017 the FFmpeg developers
built with gcc 4.9.2 (Debian 4.9.2-10)
configuration: --enable-cross-compile --arch=i686 --target-os=linux --disable-yasm --disable-static --enable-shared --enable-gpl --enable-libmp3lame --enable-libx264 --enable-libsoxr --enable-version3 --enable-nonfree --enable-openssl -[b][color=#FF0000]-disable-decoder=ac3 --disable-decoder=ac3_fixed --disable-decoder=eac3 --disable-decoder=dca --disable-decoder=truehd --disable-encoder=ac3 --disable-encoder=ac3_fixed --disable-encoder=eac3 --disable-encoder=dca --disable-decoder=hevc --disable-decoder=hevc_cuvid --disable-encoder=hevc_nvenc --disable-encoder=nvenc_hevc[/color][/b] --extra-ldflags='-L/root/daily_build/64_14/4.4.x/LinkFS/usr/lib -L/root/daily_build/64_14/4.4.x/Model/TS-X72/build/RootFS/usr/local/medialibrary/lib -Wl,--rpath -Wl,/usr/local/medialibrary/lib' --extra-cflags='-I/root/daily_build/64_14/4.4.x/LinkFS/usr/include -I/root/daily_build/64_14/4.4.x/Model/TS-X72/build/RootFS/usr/local/medialibrary/include -D_GNU_SOURCE -DQNAP' --prefix=/root/daily_build/64_14/4.4.x/Model/TS-X72/build/RootFS/usr/local/medialibrary
libavutil 55. 58.100 / 55. 58.100
libavcodec 57. 89.100 / 57. 89.100
libavformat 57. 71.100 / 57. 71.100
libavdevice 57. 6.100 / 57. 6.100
libavfilter 6. 82.100 / 6. 82.100
libswscale 4. 6.100 / 4. 6.100
libswresample 2. 7.100 / 2. 7.100
libpostproc 54. 5.100 / 54. 5.100
-QNAP eliminated QVHelper a few months ago, so that until they re-implement the relevant codec, we can not visualize this content as well as
The Workaround:
QNAP uses an old name, ffmpeg, for transcoding. The current version using QNAP from ffmpeg is compiled effectively without support for some codecs. However, it would be (and is) possible to use another compilation of ffmpeg with much more extended support, and replace it with QNAP.
The most "simple" way is to install ffmpeg from a third-party repository, and make the change by accessing SSH. Of course you can use your own compilation, but you have to keep in mind that we have different architectures, and different hardware features. You could create an automatic script that did everything, but I'll leave it for someone else who wants to do it, since depending on the NAS, Disks installed and another stuff, the path/files to be modified will be different.
In my case, using a TS-253Be:
1º. Install ffmpeg statically compiled for your architecture (Maybe you can use ffmpeg from qnap club repository)
2º. Make a backup of old ffmpeg
Code: Select all
mv /usr/bin/ffmpeg /usr/bin/ffmpeg.bak
mv /share/CACHEDEV1_DATA/.qpkg/CodexPack/opt/cdx/bin/ffmpeg /share/CACHEDEV1_DATA/.qpkg/CodexPack/opt/cdx/bin/ffmpeg.bakCode: Select all
ln -s /share/CACHEDEV1_DATA/.qpkg/ffmpeg/ffmpeg /usr/bin/ffmpeg
ln -s /share/CACHEDEV1_DATA/.qpkg/ffmpeg/ffmpeg /share/CACHEDEV1_DATA/.qpkg/CodexPack/opt/cdx/bin/ffmpegAfter a CodePack or system update, probably we have to make the change again.
To revert back, you only need to move again the original files:
Code: Select all
mv /usr/bin/ffmpeg.bak /usr/bin/ffmpeg
mv /share/CACHEDEV1_DATA/.qpkg/CodexPack/opt/cdx/bin/ffmpeg.bak /share/CACHEDEV1_DATA/.qpkg/CodexPack/opt/cdx/bin/ffmpeg1º. qnap will continue to detect the video as not supported, but we can reproduce it anyway.
2º. by default, ffmpeg maybe dont use GPU to assist transcoding, so you will need a powerfull CPU, another ffmpeg, some tweaks or another ffmpeg after all
3º. I dont know why, but dont work for all videos (same codecs, same resolution...), maybe CPU transcoding limitation
4º. And in any case, transcoding will not be possible on high bitrate, at least in my hardware
Not all ffmpeg copies should be replaced, ffmpeg in /usr/local/medialibrary/bin/ffmpeg need to be the original one, only replace the two above