Can't convert FLV to MP4 for iPhone with ffmpeg

Question

I'm having issues with converting an FLV to an MP4 that will play on iPhone/iPad via Video-js.

It seems that the ffmpeg commands are not converting properly.

Here's one of the original commands that the software, cumulusclips, is running on conversion:

/usr/bin/ffmpeg -i /var/www/html/cumulus/cc-content/uploads/temp/M2q9rmYjSkElrCJA34Cr.avi -s 640x480 -vb 800k -ac 2 -ab 96k -ar 44100     -f flv /var/www/html/cumulus/cc-content/uploads/flv/M2q9rmYjSkElrCJA34Cr.flv

Output similar to the following:

Input #0, avi, from '/var/www/html/cumulus/cc-content/uploads/temp/M2q9rmYjSkElrCJA34Cr.avi':
  Metadata:
    ISFT            : MEncoder 2:1.0~rc2-0ubuntu13
  Duration: 00:09:56.45, start: 0.000000, bitrate: 9586 kb/s
    Stream #0.0: Video: msmpeg4v2, yuv420p, 1920x1080, 24 tbr, 24 tbn, 24 tbc
    Stream #0.1: Audio: mp3, 48000 Hz, 2 channels, s16, 160 kb/s
Output #0, flv, to '/var/www/html/cumulus/cc-content/uploads/flv/M2q9rmYjSkElrCJA34Cr.flv':
  Metadata:
    encoder         : Lavf52.64.2
    Stream #0.0: Video: flv, yuv420p, 640x480, q=2-31, 800 kb/s, 1k tbn, 24 tbc
    Stream #0.1: Audio: libmp3lame, 44100 Hz, 2 channels, s16, 96 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
  Stream #0.1 -> #0.1

After this, it's running the following for mobile:

/usr/bin/ffmpeg -i /var/www/html/cumulus/cc-content/uploads/temp/M2q9rmYjSkElrCJA34Cr.avi -s 480x360 -vb 600k -ac 2 -ab 96k -ar 44    100 -f mp4 /var/www/html/cumulus/cc-content/uploads/mobile/M2q9rmYjSkElrCJA34Cr_temp.mp4

Output:

Input #0, avi, from '/var/www/html/cumulus/cc-content/uploads/temp/M2q9rmYjSkElrCJA34Cr.avi':
  Metadata:
    ISFT            : MEncoder 2:1.0~rc2-0ubuntu13
  Duration: 00:09:56.45, start: 0.000000, bitrate: 9586 kb/s
    Stream #0.0: Video: msmpeg4v2, yuv420p, 1920x1080, 24 tbr, 24 tbn, 24 tbc
    Stream #0.1: Audio: mp3, 48000 Hz, 2 channels, s16, 160 kb/s
Output #0, mp4, to '/var/www/html/cumulus/cc-content/uploads/mobile/M2q9rmYjSkElrCJA34Cr_temp.mp4':
  Metadata:
    encoder         : Lavf52.64.2
    Stream #0.0: Video: mpeg4, yuv420p, 480x360, q=2-31, 600 kb/s, 24 tbn, 24 tbc
    Stream #0.1: Audio: libfaac, 44100 Hz, 2 channels, s16, 96 kb/s

Answer 1

I'm fairly certain that the ffmpeg version you're using is quite outdated. Please download a static build for your system from the official homepage and use the path to the new ffmpeg instead of the old /usr/bin/ffmpeg.

For example, if you downloaded your static build, you could put it to /usr/local/bin/ffmpeg, make it executable (chmod ugo+x /usr/local/bin/ffmpeg) and then use that.

Then, you want a command like this to convert a video to an MP4 that's HTML5-ready and playable by all kinds of mobile devices:

ffmpeg -i input.avi -c:v libx264 -c:a aac -strict experimental -b:a 128k \
-crf 23 -profile:v baseline -movflags faststart output.mp4

Vary the CRF depending on what quality you want (18–28 is a good range, lower means better), or choose -b:v 2M for fixed-bitrate encoding at 2 MBit/s, for example.

The original conversion was using MPEG-4 Part 2 video instead of MPEG-4 Part 10, which should be supported by mobile devices, but doesn't necessarily have to be. It's safer that way.

Also, these days, you really do not need to create FLV videos. I am not aware of any device or playback technology that would require this (a little antique) format.

You may be interested in this, too: What bunch of ffmpeg scripts do I need to get HTML5-compatible "Video for everybody"?