Problem with x264 2-pass encoding (profiles)

09Feb2012 Posted by jdamen

So...

I experience quite some problems with the standard H264 2-pass transcoding profiles. Searched this forum and find out to run some ffmpeg command line tests.

for example this works:
ffmpeg -i /mnt/mediamosa/data/G/G2MJkXvRFTUhpuIQDIruhBQ2 -acodec libfaac -vcodec libx264 -vpre slow -b 536000 -r 25 testvid.mov

and this won't work (2-pass):
ffmpeg -i /mnt/mediamosa/data/G/G2MJkXvRFTUhpuIQDIruhBQ2 -acodec libfaac -ab 128000 -ar 44100 -ac 2 -vcodec libx264 -pass 2 -s 640x350 testvid.mov
Cannot read file 'ffmpeg2pass-0.log': No such file or directory
Error reading log file 'ffmpeg2pass-0.log' for pass-2 encoding

So i read a lot about it and found out that for the 2-pass encoding FFMPEG needs to write a logfile which it will use at the 2nd pass to improve what it did in the 1st pass, and that ffmpeg can get a parameter -passlogfile, but where is it stored by mediamosa?

I don't read anything about these problems on this forum so maybe something is wrong with my ffmpeg or permissions, location of the temp log files ?

Earlier i experienced problems with all libx264 transcodings because the preset files were missing, i managed to get them online so that is fixed.

Tried to find some info here: http://drupal.org/node/1070698 , but like to hear from some of you.

Thanks!

Comments

Jdamen, MediaMosa transcodes

Posted by forgacs on February 15th, 2012 - 14:07

Jdamen,

MediaMosa transcodes the video files in this directory:
@you_san_nas_location/data/transcode
Eg. /srv/mediamosa/data/transcode

When MediaMosa uses a 2 pass encoding, then it creates a temporary directory:
Eg. jNAZadDlRdTbpnSPFhKlH5AP_dir
Where the first part is the mediafile id.

Then the log file is created and used there.
Does your system has enough rights to create, use and remove this directory?

Thanks

Posted by jdamen on February 21st, 2012 - 14:37

thanks for your reply.

So if the apache (www-data) user is owner and has rights it should be ok?

drwxr-xr-x 2 www-data www-data 16384 Feb 21 2012 transcode

above are the settings of the folder /mountpoint/data/transcode.
when i switch to apache user i can create and remove directories in the folder /data/transcode

any other idea ?

> So if the apache (www-data)

Posted by forgacs on February 28th, 2012 - 10:46

> So if the apache (www-data) user is owner and has rights it should be ok?
Yes, it should be ok.

Please try to run it as apache user in data/transcode directory:
ffmpeg -i /mnt/mediamosa/data/G/G2MJkXvRFTUhpuIQDIruhBQ2 -acodec libfaac -ab 128000 -ar 44100 -ac 2 -vcodec libx264 -pass 2 -s 640x350 testvid.mov

What does happen?

Problem with x264 2-pass encoding (profiles)

Comments

Jdamen, MediaMosa transcodes

Thanks

> So if the apache (www-data)

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