Bluray

State of play as of March 2009. Hopefully things will improve...

Rip

Until recently the only way to rip Bluray discs on a PC is with AnyDVD HD in Windows. Now you can skip several steps by using MakeMKV instead. This will produce a Matroska file with the desired streams you select - leave out all the subtitles and foreign language dub tracks.

Modified MPEG-TS Container

Bluray video is stored in a modified version of the MPEG-TS container format in the BDMV/STREAM folder. The modification is an extra 4 byte time code on each MPEG-TS packet, increasing the packet size from 188 bytes to 192 bytes, apparently in order to better support buffering and out-of-order writing to random-access media. It is unclear whether this is an MPEG Committee sanctioned modification, but there appears to be some standardisation through something called AVCHD. So in theory, a decrypted M2TS file should be sufficient for playback, but many players still choke on it expecting the normal MPEG-TS format.

We can also use tsmuxer^[1] to deal with M2TS files, and in particular extract the AC3 and DTS cores from TruHD and HD Master Audio tracks respectively.

Transcode

Transcode to H.264

In this example, I am processing my Bluray copy of Baraka.

Now we can use ffmpeg to squash the video track from 28 GB down to about 10 GB using the constant rate factor quality setting:

ffmpeg -i Baraka.mkv -acodec copy -vcodec libx264 -crf 20 Baraka.mkv

Crop

Since Baraka has 102 pixels of letterbox top and bottom, we crop thus:

ffmpeg -i 00017.ac3 -acodec copy -i 00017.vc1 -vcodec libx264 -crf 20 \
    -croptop 102 -cropbottom 102 -aspect 1920:876 Baraka.mkv

Note in the -aspect option we need to subtract the crops from the normal 1920:1080 aspect ratio.

H.264 options

For best quality, we can improve the H.264 options on the ffmpeg command line.^[2]

Single pass constant rate factor (CRF) is best, since two-pass is only relevant if we care about exact file size. Since quality is paramount, I should also use B frames as references, turn CABAC and trellis encoding on, bump up the motion estimation and subpixel searching methods, and use multiple threads to speed it up:

ffmpeg -i 00017.ac3 -acodec copy -i 00017.vc1 -vcodec libx264 -crf 20 \
    -croptop 102 -cropbottom 102 -aspect 1920:876 \
    -bf 16 -refs 5 -coder 1 -trellis 2 -me_method umh -subq 7 -threads 4 Baraka.mkv

Or for a crazy HQ encode that takes ages, increase the motion estimation range (good for HD), turn on the 8x8 DCT, enable weighted B frame prediction and mixed reference frames (especially if using multiple B frame references), and disable the fast P frame skip for smoother skies and plain areas:

ffmpeg -i 00017.ac3 -acodec copy -i 00017.vc1 -vcodec libx264 -crf 20 \
    -croptop 102 -cropbottom 102 -aspect 1920:876 \
    -bf 16 -refs 5 -coder 1 -trellis 2 -me_method umh -subq 7 -threads 4
    -me_range 32 -flags2 +dct8x8+wpred+bpyramid+mixed_refs-fastpskip Baraka.mkv

This produces great quality, highly efficient encoding (small file size), at the expense of very long encoding time and high CPU demand at decoding time.

Cartoons

For anime and cartoons, bump up the deblocking and noise reduction filters:

ffmpeg -deblockalpha 2 -deblockbeta 2 -nr 150 ...

Subtitles

Bluray subtitle streams currently need converting to SUB/IDX format before they will reliably go in Matroska files. This conversion can easily be done with BDSup2Sub^[3]. Choose Lanczos3 for best quality if changing resolution.

M2TS file MIME Type

Ubuntu still doesn't see these files as video files - edit /usr/share/mime/packages/bluray.xml and copy in this:

<?xml version="1.0" encoding="UTF-8"?>
<mime-info xmlns='http://www.freedesktop.org/standards/shared-mime-info'>
  <mime-type type="video/bluray">
    <alias type="application/bluray"/>
    <alias type="video/avchd"/>
    <sub-class-of type="video/mpeg"/>
    <comment>Blu-ray/AVCHD Video</comment>
    <magic priority="50">
      <match value="\x47\x40\x00\x10\x00\xb0\x00\x11" type="string" offset="4"/>
    </magic>
    <generic-icon name="video-x-generic"/>
    <glob pattern="*.m2ts"/>
    <glob pattern="*.mts"/>
  </mime-type>
</mime-info>

Then update your MIME database:

sudo update-mime-database

You should then be able to open M2TS files with an mplayer-based media player.

Playback

NVidia has VDPAU. Dear ATI, where's that fancy video acceleration you promised? In the meantime, we can speed up playback using multithreaded mplayer^[4]:

git clone git://repo.or.cz/mplayer
cd mplayer
git checkout origin/mt
git submodule init
git submodule update
sudo apt-get build-dep mplayer
./configure --prefix=/usr
make
sudo checkinstall --fstrans=no --install=no --pkgname=mplayer-mt --pkgversion "1:0.svn`date +%Y%m%d`-0.0ubuntu1" --default

mplayer -lavdopts threads=4 Baraka.mkv

And if it still sucks,

mplayer -lavdopts skipframe=nonref:skiploopfilter=all:fast=1:threads=4 Baraka.mkv

References

[1] ttp://www.smlabs.net/tsmuxer_en.html

[2] ttp://sites.google.com/site/linuxencoding/x264-ffmpeg-mapping

[3] ttp://www.videohelp.com/tools/BDSup2Sub

[4] ttp://www.mplayerhq.hu/design7/news.html

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