Correcting playback speed

[ursamtl]

I have an mpeg file containing some mid-70s super-8 concert footage. The playback speed is obviously too fast and the audio is one full tone up. I'd like to adjust this down to the correct speed. What are my options?

Sorry if this has been discussed before in the forum. I've tried several searches but without any answers.

Thanks,
Steve.

[Arky]

What format is your MPEG file? i.e. what resolution, what bitrate etc.?

Your options are somewhat limited, from a quality perspective. Resampling MPEG footage is never going to yield a top quality result, unfortunately.

If the MPEG file is a multiplexed file, you could demultiplex it (TMPGEnc's 'MPEG Tools' will do that for you), and then drop the resulting elementary MPEG stream into an NLE that caters for editing of MPEG (e.g. Ulead Media Studio Pro, Canopus Edius, Pinnacle Liquid) and apply a timewarp to the file, rendering this to a new MPEG file - however, as I noted above, you are going to experience a severe quality hit when modifying an MPEG file in this way.

Alternatively, you might find it worthwhile experimenting with frameserving the file, using AVIsynth, or creating a virtual AVI file which can then be operated upon to transcode a new MPEG file of different speed/duration.

Obviously, whichever option you choose, you'd also need to 'stretch' the elementary audio stream to match the video, possibly in the NLE itself, or using an audio editor such as CoolEdit/Audition, or Soundforge (it might be necessary to transcode the audio file to a 16bit wav file first, if the audio compression is not supported by your audio editor).

Sorry it's not a perfect solution, but your options are, unfortunately, a little limited with such poor source material.


Arky ;o)

[ursamtl]

Just to follow up, I successfully corrected the speed last night using an avisynth script to slow the frame rate and audio. I also resized and cropped some rough edges then frameserved the whole thing to TMPGEnc. It was simple and it worked beautifully.

Thanks for the tip.
Steve.