Trimming an Mpeg-2?

[ultrazero]

I have an mpeg-2 that I transferred from my ReplayTV to my mac using DV-archive. I'd like to trim the file a little bit (commercials before and after) and then burn it to dvd.

How do I trim it on a mac? Is there any hope for a cheap solution?

[galactica]

ffmpegx, gumby, mpgtxwrap, quicktime with mpeg2 playback component and export.....

[ultrazero]

something tells me this has been asked before. I did a search. I swear.

QT w/mpeg2 component: I was under the assumption if you export, you'll only get video?

[galactica]

ahhh i didnt know you wanted to do both video and audio, makes since though.

personally id use mpgtxwrap using split according to range
HH:MM:SS are allowable inputs into the range area, and then you just push split.

been a while since i used hh:mms setings but i thnk you just put them in with , inbetween then push split and it splits them at those marks.

quicktime shoudl give you accurate enough time marks, if not try opening it in VLC or something that shows progression of time.

[ZeroSix]

using mpgtxwrap is a good choice, but it is cumbersome. you cannot just "remove" parts of the file. you have to "split" the file based on timecode.

So say your mpeg file has one commercial break that starts at 5 minutes into the clip and lasts 2 minutes. Tell it to Split at the first 5 minutes, next two minutes, then again for remainder of the file.

Then join the first split and the last split.

Sound complicated? IT IS!

And by doing this, you will have messed up the time code on the mpeg file, so demuxing your final file and remuxing it is required.

Workarounds?

1) Convert to a high quality .avi and work with in Quicktime, then convert BACK to mpeg 2.

2) Don't record commercials.

3) Attempt to use MissingMpegEdit [never got it to work myself] http://homepage.mac.com/rnc/

4) don't bother with any of the above.

hope you found this helpful.

[dcsos]

If you exported from Quick Time
as Video Only (QuickTime Pro w/mpeg plug-in)
and used another method entirely to preserve the audio, and transcode it seperately, then use a MUXING program to combine the VIDEO and new audio track

Would you loose the sync ?

I would suggest some audio tools, but I don't know the characteristics of the sound on your type of file....
did you look at www.softarch.com.. they have some tools for copying from personal video recorders that record MPEG-2 to MACINTOSH OS 9 and X
I don't know replay..Is it using a DV format? not MPEG?

[brett]

re: encoding to dv or mjpeg or whatever to edit.

the sound is .mp2. you can encode it to .aif using itunes. (actually, does qt cut .mp2? if so, you don't need to encode the audio at all.)

encode the video to your desired high quality codec using diva. you should encode just the .m2v, though (diva doesn't like muxed mpegs if they are long).

mux the two in qtpro, adding the video to the audio. however, rtv mpegs drift out of sync after an hour or so, and they also start about 20 frames out of sync using the method above. to cure the latter problem, you manually chop frames; to solve the former, you would start the process by creating ~45 minute chunks, thus re-syncing at each chunk during the muxing process in qt. edit the products as desired. then reencode the audio and video if you need to get back to mpg. the result is great for sync and audio, and good for video (quality degrades a bit from the two additional encodings).

re: pure editing of the mpg.

zero's use of the splitter does work, but is painfully inaccurate as to where it splits the mpg, even if you have entered precise values. it just gets the time wrong.

otherwise, the only real splitter for mpeg files is made by pixela, a japanese company. you will find that pixedv costs some serious bucks as it is bundled with a hw mpeg encoder. but it works great. even better is their product "capty mpeg edit," which uses the same engine but does not grab your whole screen. unfortunately, it is only available in japanese, but that is not a huge hurdle to overcome, as you can deduce "what the buttons do" pretty easily. the resulting mpgs are fantastic. oh, you have to use a cl proggy called "demux" and then remux the product to get capty's products to accept the rtv mpg. search for it, and answers to other replay tv questions, here:

http://www.designwork.net/macreplaytv/index.php

[ZeroSix]

Agreed... I meant to mention that the use of mpegtx is very inaccurate and your timecodes will have to be based on trial and error to get it right. I have been through this several times and it is not fun.

[pants]

do you have dvd studio pro 2? you should be able to do this in it.

[MichaelLAX]

After I extract using DVArchive, I don't bother trimming commercials anymore. I just chapter after each commercial break when authoring and can easily skip commercials when in playback.

If you can get ahold of a copy of PixeDV (from pixela software, it comes bundled with the ADS Technologies USB Instant DVD for Mac), it will trim the ReplayTV MPEGs.

[ZeroSix]

in DVD SP you should also be able to jut skip the chapters like you said... You can set each chapter with a start and end time... Have one chapter END right at a commercial break, and have the next chapter START when the break is over. Should be a seamless transition, and you then won't have to "skip" over them.

I have had to do this before when capping movies from VHS where i started the VCR too early or whatever.

Works well... Sorry i didn't think of this sooner.