Best way to reencode H.264? (MPEG-4 AVC Main 3.0 --to--> Baseline 3.0) - maemo.org

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	eight	2012-02-12 , 08:11
	Posts: 106 \| Thanked: 81 times \| Joined on Dec 2011 @ /	#1

I would like to convert some videos for travelling and to view them with the N900 default video player. Mplayer and VLC support the main profile and play those videos, but they are not optimized for mobile usage, and battery drains faster.

The files I'm after are the 28c3 recordings which can be downloaded at http://mirror.fem-net.de/CCC/28C3/mp4-h264-LQ/.

They are encoded in H264 Main 3.0 Profile, according to this wiki page the n900 only supports Baseline 3.0 encoded stuff.

I don't have much experience with reencoding/conversation, just used virtualdub in the past and installed avidemux.
Can anybody give me some tips what would be the fastest/best way to reencode a bunch of H.264 Main Videos to Baseline 3.0? Any suggestions on software for linux or windows? Is it possible to use a HD5850 for conversion?

Thanks,
Conrad

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Edit: Found a N900-preset for avidemux on the wiki, will go with it for some tests.

Update: File gets bigger after reencode, from 80 Mb to 104 Mb and now shows Baseline 2.1.

Would be nice to get Baseline 3.0, maybe the compression is better.
Hints are welcome

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update: Changed bitrate to 281 Kbps, file is now 81 Mb.

Last edited by eight; 2012-02-12 at 16:25.

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The Following User Says Thank You to eight For This Useful Post:
demolition

AlekMX	2012-02-15 , 00:35
Posts: 28 \| Thanked: 12 times \| Joined on Nov 2010	#2

If you want a detailed article about video encoding and playback on the N900 I strongly suggest going to this link:

http://wiki.maemo.org/Video_encoding#Encoding_Software

There's even an optimized preset for the N900 for different video converters. I personally use Handbrake (download link also on the link I provided) and it works like a charm.

Good luck and regards.

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demolition	2012-02-15 , 01:39
Posts: 560 \| Thanked: 422 times \| Joined on Mar 2011	#3

Do you want something that will convert on device, or via a pc?

The line you might expect to work, when trying to convert, doesnt...

Code:

ffmpeg -i input.mp4 -vcodec copy -acodec copy -vpre baseline output.mp4

Knowing an effective command to re-encode video mdeia which is already in H264 format, so doesn't need converting, would be really handy. If specifying the codec is required to change profiles, what is the ffmpeg name on the N900 for the libav vcodec and acodec?

Oh, another reason the above might not work is that the -vpre preset seems to require the full file path. I read somewhere the order and combinations of presets can also make a difference. Dodn't know though.