How do I capture a small part of a long video stream?

July 7, 2009 10:16 AM

I want to capture a small part of a long video stream from the web. And I want it in mp4.

It's my convocation webcast, and it's in asf. I have managed to capture just the five minutes (of 2+ hrs!) I want, but I did so with Real Player and so the file is in the ever-unfriendly rm file format. I haven't had any luck with file conversion programs, and I can't crack the nut which is VLC (I've tried the VideoLAN forums). I'm running WinXP, and I'm looking for a free way to do this.

I need a recommendation for a tried and true free file conversion that deals with rm->mp4; or step-by-step instructions for how to do this with VLC (I don't want the entire file). I did look in the back posts, but didn't find anything dealing with a partial capture. Many thanks, mefites.

posted by tamarack to Computers & Internet (6 answers total)

Have you looked into using ffmpeg? It's command-line (there are probably guis available), but the easiest method of converting files I know.
posted by Lemurrhea at 10:36 AM on July 7, 2009

Seconding ffmpeg, and there is indeed a gui available. There are apparently some instructions here, though I'm not sure if it'll definitely work.
posted by movicont at 11:02 AM on July 7, 2009

imho Super is the best free video conversion app available and

>converts input RM RAM RMVB RA (RealMedia) files to any other format

it also runs ffmpeg ...
posted by fistynuts at 12:20 PM on July 7, 2009

Response by poster: Neither WinFF nor Super will let me convert the rm video file. I suppose its possible that since it's a partially saved bit from an overall file perhaps something has made it less readable to these programs. (WinFF tells me it's an invalid file. Super gives me a generic it-could-be-anything message). Oh, and the rm file does play fine for me.
posted by tamarack at 3:52 PM on July 7, 2009

If you have the disk space, I would use mplayer -dumpstream to capture the entire file, and then use mencoder -ss [start] -endpos [length] to extract the part you want.
posted by russilwvong at 5:15 PM on July 7, 2009

then it sounds to me like the stream is lacking headers/or currupt - this may be due to the way you are capturing it or some sites are corrupting the streamed files such that they will only play on their custom webplayer.
posted by fistynuts at 7:33 AM on July 8, 2009