Video editing n00b

June 5, 2009 1:08 PM

Please recommend a free, reliable program that will allow me to crop and edit .mp4 videos.

I have a Sanyo Xacti that takes video in .mp4 format. I am looking for a free, reliable program that will allow me to crop these video clips. Other editing features could be nice, too - although I imagine trimming the beginning and ends off of clips will be the primary task.

I'll be using DVD Flick to create .iso files for burning. Programs that allow me to edit the clips and create isos would be worth considering, too.

posted by gnutron to Technology (6 answers total)

Try Avidemux. It's free software and cross-platform. As always, make sure to cut on keyframes to avoid garbled frames or audio sync issues.

With regard to cropping, that's never a lossless process: you must re-encode to crop. If DVD Flick accepts Avisynth input, consider making an AVS Script from your source MP4 so you can crop and encode to DVD format in one step. If not, and you have the hard disc space, you can do a lossless rendering pass to something like HuffYUV to ensure that you're only doing lossy->lossy conversion once.
posted by Inspector.Gadget at 1:14 PM on June 5, 2009

Windows Movie Maker does that, and it's already on your PC if you have XP SP2. You'll need to use FFMPEG to convert the videos to AVI first as WMM doesn't support the MP4 file format.
posted by COD at 1:46 PM on June 5, 2009

Second avidemux. As Inspector.Gadget said, you can cut at keyframes (using the buttons that skip back and forth between keyframes) to make cuts without any loss in quality, but for anything else you'll need to re-encode it when you save it.
posted by burnmp3s at 2:07 PM on June 5, 2009 [1 favorite]

If you're going to target DVD anyway, it might pay to look at converting to MPEG-2 first before the editing step - yes, the general rule-of-thumb is to do your editing in the source format then convert to target format as your final step, but MPEG-2 editors are easier to come by (and generally better/more sophisticated) than MPEG-4 editors, particularly ones that can handle the .mp4 container.

Personally, to be totally cheapskate, I'd use OSS/freeware tools to convert your .mp4 to an MPEG-2 .MPG & separate audio stream (avisynth can do this using DirectShowSource, cropping/resizing at the same time), then use something like Cuttermaran with one of the provider add-ons to do frame accurate cutting. Cuttermaran will edit losslessly, except for the few frames between the previous/next keyframe and the cutpoint - this is pretty much unavoidable with any compressed format, but I've yet to see an .mp4 editor which won't recode the whole thing when cutting between keyframes.
posted by Pinback at 3:55 PM on June 5, 2009

Sorry to get back to this thread so late. Ordinarily your suggestion would make sense, Pinback, but many DVD players are finicky about GOP length and cutting in MPEG-2 introduces that particular wrinkle.
posted by Inspector.Gadget at 7:35 PM on June 6, 2009

And, back even later... Agreed, but if you pick the right add-on & encoder, you can set the max GOP length (so that e.g. you get a short GOP, or a normal-sized GOP and a short one). Remember, GOP length specs for DVD (15 frames/GOP for PAL; 18, IIRC, for NTSC) are maximum lengths - a GOP of a single frame is just as valid (& in fact necessary, as that's how most DVD menus are made).

Still, it's been years since I came across a DVD player that picky about non-standard GOPs - the situation might be different in NTSC-land but, here in PAL-land, most pay-tv providers & half the damned FTA stations have been transmitting digital with huuuuuuge GOPs (I've seen up to 48 frames/GOP!) for years, so it's no surprise the same hardware decoders end up in DVD players.
posted by Pinback at 4:23 PM on June 7, 2009