Some Hellalame Blog

This is a rough how to solution of how I convert mts/m2ts (h264) files from an HD Camcorder into mp4 video files that are playable on the xBox 360. The source mts/m2ts files are from a Canon HD Camcorder.

The Basics for this process are:

• Build/compile all of the libraries & binaries to do the video conversion on a linux system
• Use mencoder to de-compress the mts/m2ts video file into a (mostly) uncompressed avi file.
• Then use ffmpeg to re-compress the avi file using the x264 library back into a small HD file that the xBox 360 can understand & play

Step 1) I just used a spare computer, turning it into linux system (I have a decent working knowledge of linux, mostly in some sort of server capacity though). For this video conversion system I started with the desktop version of Ubuntu 9.10, and followed this thread in order to build the required video binaries:

http://ubuntuforums.org/showthread.php?t=786095

It worked well for the most part, but I ended up having to manually create symlinks (ln -s) in /usr/lib for the x264 lib:

/usr/lib/libx264.so -> /usr/local/lib/libx264.so
/usr/lib/libx264.so.88 -> /usr/local/lib/libx264.so.88

After doing this, ffmpeg finally saw the libx264 files, and would link to them when compiling.

Step 2) Once all the ffmpeg / mplayer / libx264 programs and libs were installed and configured properly. mencoder (mplayer) needed to be setup to uncompress the mts/m2ts files.

WARNING: These uncompressed video files are HUGE!

The following command was used to uncompress the mts/m2ts files, and was taken from here:

http://www.avsforum.com/avs-vb/showthread.php?t=789775&page=6


mencoder HD_Camcorder_file.mts -fps 60000/1001 -noskip -mc 0 -oac pcm -demuxer lavf -vf pullup,softskip -ofps 24000/1001 -ovc lavc -lavcopts vcodec=ffvhuff:format=YV12:vstrict=-1:aspect=16/9 -o UNCompressed_Video.avi

It should be noted that a couple of the mencoder options are used specifically for the Canon “pulldown” removal (more information about that is in the avsforum thread).

Also note that the -ofps option is set for 24,000/1001 to best decode the “24FP” fps recording option on the camcorder. There are circumstances where this needs to be changed to 30000/1001 which seems to be for the “60i” fps recording option. The final script below shows how this is auto-detected, and can automatically be adjusted for as needed.

Step 3) The final step is to re-encode the uncompressed avi video using the x264 library and an ffmpeg command:

ffmpeg -y -i UNCompressed_Video.avi -acodec libfaac -vcodec libx264 -vpre xbox360 -ab 192kb -b 17000k -v 0 -f mp4 xBox_HD_Video.mp4 </dev/null

As you can see this ffmpeg command requires that a special “predefined” encoding profile is used. Which is named “xbox360″. This ffmpeg profile is stored in the appropriate ./shared/ directory on the linux system, on my system the full path to the file is:

/usr/local/share/ffmpeg/libx264-xbox360.ffpreset

And the contents of this ffmpeg “predefined” profile uses these parameters:

coder=1
flags=+loop
cmp=+chroma
partitions=+parti8x8+parti4x4+partp8x8+partb8x8
subq=5
me_range=16
g=250
keyint_min=25
sc_threshold=40
i_qfactor=0.71
rc_eq=blurCplx^(1-qComp)
qcomp=0.6
qmin=10
qmax=51
qdiff=4
bf=3
refs=4
trellis=1


All of the parameters for that ffmpeg “predefined” profile needed for playback on the xBox 360 were learned about from this web page:

http://www.dslreports.com/forum/r19076412-How-to-transcode-video-with-ffmpeg-for-the-Xbox-360

It should also be noted that at the very end of that ffmpeg command is the parameter: “
This tells ffmpeg to accept incoming keyboard commands from /dev/null. Which basically tells ffmpeg NOT to accept ANY incoming commands. This final parameter is very important when trying to run the ffmpeg re-encoding process in the background through a shell script via a cronjob.