Making Videos Playable on Android and iPhone

You might want to convert you home-made video (no pirated video :-!) into a format that your Android phone can play. The video formats that Android support are listed in Android developers' site:

http://developer.android.com/guide/appendix/media-formats.html

Among the listed formats, H.264 (as a realization of the MPEG-4 standard) has been well accepted by the industry. Companies including Apple has switched to it. In the following, I will show you that using open source software on a Linux box can convert your video into H.264 with AVC video and AAC audio. I took the following post as a reference, but with updates.

First of all, you need to install the following software packages:

1. mplayer: a multimedia player
2. mencoder: MPlayers's movie encoder
3. faac: an AAC audio encoder
4. gpac: a small and flexible implementaiton of the MPEG-4 system standard
5. x264: video encoder for the H.264/MPEG-4 AVC standard

Then we do the following steps to convert the video.avi into a .mp4 file in H.264 format.

1. Extract the audio information from video.avi using MPlayer:

   mplayer -ao pcm -vc null -vo null video.avi

   This will generate a audiodump.wav file.
   


2. Encode audiodump.wav into AAC format

   faac --mpeg-vers 4 audiodump.wav

   This generates a audiodump.aac file.


3. Use mencoder to convert the video content of video.avi into YUV 4:2:0 format, and use x264 to encode the output into AVC format
   

   mkfifo tmp.fifo.yuv
   mencoder -vf scale=800:450,format=i420 \
    -nosound -ovc raw -of rawvideo \
    -ofps 23.976 -o tmp.fifo.yuv video.mp4 2>&1 > /dev/null &
   x264 -o max-video.mp4 --fps 23.976 --bframes 2 \
    --progress --crf 26 --subme 6 \
    --analyse p8x8,b8x8,i4x4,p4x4 \
    --no-psnr tmp.fifo.yuv 800x450
   rm tmp.fifo.yuv

   We created a named pipe to buffer between mencoder and x264. These command lines generate both Quicktime-compatible and H.264-compatible content. This is because Apple Quicktime can now hold H.264 content. Be aware to specify the same video size to mencoder and x264. In above example, the size is 800x450.


4. Merge the AAC audio and AVC video into a .mp4 file using gpac

   MP4Box -add max-video.mp4 -add audiodump.aac \
     -fps 23.976 max-x264.mp4

   MP4Box is a tool in the gpac package.