Convert a video to MP4 (H.264/AAC) with ffmpeg - linux

Question

If I don't make a mistake, Safari currently need MP4 (H.264/AAC) video encoded for the HTML5 <video> element.
So I tried to convert a video to this format with ffmpeg. However when I enter the shell command ffmpeg -i video.flv video.mp4, the returned error is :
Seems stream 0 codec frame rate
differs from container frame rate:
2000.00 (2000/1) -> 29.92 (359/12) Input #0, flv, from 'video.flv':
Duration: 00:05:01.20, start:
0.000000, bitrate: 66 kb/s
Stream #0.0: Video: h264, yuv420p, 320x240 [PAR 1:1 DAR 4:3], 66 kb/s,
29.92 tbr, 1k tbn, 2k tbc
Stream #0.1: Audio: aac, 22050 Hz, stereo, s16 Output #0, mp4, to
'video.mp4':
Stream #0.0: Video: mpeg4, yuv420p, 320x240 [PAR 1:1 DAR 4:3],
q=2-31, 200 kb/s, 90k tbn, 29.92 tbc
Stream #0.1: Audio: 0x0000, 22050 Hz, stereo, s16, 64 kb/s Stream
mapping: Stream #0.0 -> #0.0
Stream #0.1 -> #0.1 Unsupported codec
for output stream #0.1
An AAC codec is required but I'm quite newbie with ubuntu and I dont really now how to fix this problem. I'm using Ubuntu 9.10 Karmik Koala (for amd64).
Thank you very much. :)

Answer 1

http://handbrake.fr is a nice high level tool with a lot of useful presets for mp4 for iPod, PS3, ... with both GUI and CLI interfaces for Linux, Windows and Mac OS X.
It comes with its own dependencies as a single statically linked fat binary so you have all the x264 / aac codecs included.
$ HandBrakeCLI -Z Universal -i myinputfile.mov -o myoutputfile.mp4
To list all the available presets:
$ HandBrakeCLI -z

Answer 2

Software patents led Debian/Ubuntu to disable the H.264 and AAC encoders in ffmpeg. See /usr/share/doc/ffmpeg/README.Debian.gz.
So go install x264, mplayer/mencoder, and Nero's AAC encoder. (Or, if you want to use all Free software, and don't care so much about audio quality, then sudo aptitude install faac.)
I don't remember if the medibuntu package of mencoder includes x264 vid encoding, since I build my own from git x264 and svn mplayer sources. (x264 is very actively developed, with significant quality and speed improvements frequently added.)
http://git.videolan.org/?p=x264.git;a=summary
x264 is also packaged, but you should check that it's up to date enough to include weightp with recent bugfixes, and even more recent speed improvements...
Or if you're already willing to convert from .flv, instead of going from the high-quality source the flv was made from, then probably whatever recent version of x264 you can find will be fine.

Answer 3

You're trying to convert a (rather rare) .flv file that (already) contains H.264 video and AAC audio.
Formatting your console's output as FFmpeg brings out these details.
Input #0, flv, from 'video.flv':
Duration: 00:05:01.20, start: 0.000000, bitrate: 66 kb/s
Stream #0.0: Video: h264, yuv420p, 320x240 [PAR 1:1 DAR 4:3], 66 kb/s, 29.92 tbr, 1k tbn, 2k tbc
Stream #0.1: Audio: aac, 22050 Hz, stereo, s16
The original flv is converted to an .mp4 file with H.264 video and AAC audio (just like the original .flv):
Output #0, mp4, to 'video.mp4':
Stream #0.0: Video: mpeg4, yuv420p, 320x240 [PAR 1:1 DAR 4:3], q=2-31, 200 kb/s, 90k tbn, 29.92 tbc
Stream #0.1: Audio: 0x0000, 22050 Hz, stereo, s16, 64 kb/s
Because the audio and video data in the .flv are already in the format/codecs you need for the .mp4, you can just copy everything to the new .mp4 container. This process will be massively faster than decoding and reencoding everything:
ffmpeg -i video.flv -vcodec copy -acodec copy video.mp4
or more simply:
ffmpeg -i video.flv -codec copy video.mp4
##The real error you're getting is:##
Unsupported codec for output stream #0.1
Which means FFmpeg can't convert audio (stream #0.1) to AAC.
You can skip the error by:
copying the audio data since it's already AAC encoded (use the copy command above)
or you can solve the error by:
using a FFmpeg build with AAC decode/encode support. FFmpeg currently supports 4 AAC libraries (see FFmpeg and AAC Encoding Guide).
For more details you should also read Converting FLV to MP4 With FFmpeg The Ultimate Guide

Answer 4

You need to recompile ffmpeg (from source) so that it supports x264. If you follow the instructions in this page, then you will be able to peform any kind of conversion you want.

Answer 5

You can also try adding the Motumedia PPA to your apt sources and update your ffmpeg packages.

Answer 6

Had this problem recently with converting nasty WMV into Final Cut Pro X for editing. Flow player can do it but it leaves a water mark, so I fiddled a bit with ffmpeg till I got something going.
First install ffmpeg - I used
brew install ffmpeg
Obviously you need brew installed first, google that bit.
Next I wrote a simple command line script with the following content - you can substitute the $1 for an input / output file or just create a shell script file...
vi convert.sh
Paste.
echo "Pass one"
ffmpeg -y -i "$1" -c:v libx264 -preset medium -b:v 1555k -pass 1 -c:a libfaac -b:a 256k -f mp4 /dev/null &&
echo "Pass two"
ffmpeg -i "$1" -c:v libx264 -preset medium -b:v 1555k -pass 2 -c:a libfaac -b:a 256k "$1.mp4"
Then to convert your video...
sh convert.sh myvideofile.wmv
If all went well you should see a new file called myvideofile.wmv.mp4.
Hope that works for you.

Answer 7

You need to compile ffmpeg with an AAC encoder. You can find one at AudioCoding.

Answer 8

Try This one:: Libav in Linux
Installation: run command
sudo apt-get install libav-tools
Video conversion command::Go to folder contains the video and run in terminal
avconv -i oldvideo.flv -ar 22050 convertedvideo.mp4