[mythtv-users] convert recordings to h264

Nick Rout nick.rout at gmail.com
Fri Dec 11 05:44:07 UTC 2009

On Fri, Dec 11, 2009 at 3:54 AM, Ian Barton <lists at manor-farm.org> wrote:
> Adam Skinner wrote:
>> Hi list.
>> I've been trying to convert my myth recordings to H.264 suitable for
>> playing on an android phone. Im currently using ffmpeg to convert the
>> videos using a recent svn version of both ffmpeg and x264.
>> Videos do convert - but Im having trouble with AV sync on 40% of them. I
>> think its because some of my recordings from UK DVB-T have reception
>> problems. Myth TV handles the AV Sync fine for these recordings. (as its
>> great)
>> Im using a one pass encoding in a script setup as a user job with
>> settings like:
>> ffmpeg -v 0  -i "${directory}/${file}"  -acodec libfaac -ab 64k -ac 1 -s
>>  ${width}x${height} -r 12 -vcodec libx264 -vpre hq -vpre ipod320 -b 250K -bt
>> 288K -metadata "title=${title}" -threads 0 -f ipod
>> "${directory}/android_tmp/${file}.mp4"
>> Would a two pass encoding help my AV sync problems?
>> File size and/or quality isn't that important. AV sync is.
>> Also can anyone please recommend a good setting for ffmpeg for two pass
>> encoding thats pretty quick.
> I think the problem you are seeing is because the Myth audio and video are
> slightly out of sync. Editing and transcoding the file without first fixing
> the sync error makes this worse.
> You need to do a lossless transcode first before converting to h264.
> Something like:

project-x does a good job of fixing this sort of problem too, although
it won't cut your ads - although it could if you provided it with a
cutlist - which you could generate from the cutlist myth generates in
the database.

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