Topic - Change frame rate without re-encode?

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Topic Starter fmillion - Posted on Wednesday, November 11 2009 12:28:41 PM
I have some video content that was obtained from DVDs in PAL regions. The content is film content (meant for playback at 23.976 (24000/10001fps)) but, as seems common, the content was raised to 25.000fps. The audio is accordingly faster.

Is it possible for me to transcode this content without re-encoding the video, so that it plays at its native 23.976fps?

Right now, I simply created a shortcut to mplayer that appends the parameter "-speed 0.959" to the playback options, which is the closest factor mplayer can get to 23.976fps. Obviously this is not right spot-on but it's close enough.

Understanding that to keep the audio compatible it'll need to remain at either 44.1k or 48khz, I'm OK with the audio being transcoded. Since there's no real need to re-encode the video though, that should obviously be avoided.

I think I can accomplish something like this with mencoder -ovc copy -oac mp3lame ... but if I specify -ofps directly then frames will either be duped or skipped, and as I said -speed is not precise. For viewing it's OK to be a bit imperfect but for archival quality obviously we'd like true 24000/1001 if possible.

Ideas anyone?