Trouble editing mkv around keyframe

[lapsang]

Dear reader,

I have a number of mkv files I wish to trim by the frame, rather than by the key frame. Using Handbrake I have tried re-encoding the mkv, as a quick Google search suggested that would help in some way. It has not. Whether mp4, or mkv, with x264, mpeg-4 or -2, I simply am not able to trim the file in places where there isn't a key frame.

I would prefer freeware where possible, if you have any suggestions. I am also keen to re-encode without sacrificing quality and want to keep as lossless as possible. I am using Mac OSX 10.9.3.

Video editing is almost entirely new to me, so I appreciate any help.

Thanks,
lapsang

[redwudz]

You might try MKV Cutter. In order to cut a highly compressed video on other than a keyframe, the editor program has to re-encode just at the cut.

EDIT: Sorry. I missed that you were on a Mac. Some of our Mac users may have some suggestions.

[ndjamena]

Last time I checked handbrake had an option to start an encode at a certain frame, I know it worked, but the audio took a second or two to kick in. Maybe they've fixed the audio bug by now. I'm assuming that's how it would 'help'. If you expected to be able to cut the file wherever you wanted afterwards you were wrong, I believe Handbrake uses the default Keyint of 250 which will likely let you cut at about 10 second intervals.

Try handbrake again and set it to start at the correct frame.

[lapsang]

I've included a screen shot of the default settings in the advanced options panel of Handbrake, because I don't entirely know what your referring to or how to do it. And I'll get to trying MKV Cutter too. Thanks.

[lapsang]

By MKV Cutter for Mac I presume you mean Boilsoft Video Splitter. I tried this before and when I imported the mkv I just got a blank screen, so I couldn't trim it as I couldn't see what I was doing. It wasn't the trial version.

[Baldrick]

It's this https://www.videohelp.com/tools/MKV-Cutter or http://forum.selur.de/topic220-mkv-cutter-tool-to-cut-h264-mkv-files-frame-accurate.html . But there is no mac version..

[lapsang]

OK - given that I posted this in the Mac section, I'm confused that someone recommended Win software. Any other suggestions? Thanks.

[poisondeathray]

You can be frame accurate, if you re-encode the entire thing (slower, lose some quality on the entire video) . You can try avidemux , there are mac versions available

It's not possible to keep it "as lossless as possible" on a Mac. Basically, you need smart rendering software, which only re-encodes a few frames around the cutsite within the affected GOP . The rest of the video is passed through untouched. SolveigMM Video Splitter, TMPGEnc Smart Renderer, Videoredo are the ones that come to mind, but are Windoze only

[lapsang]

OK, well bearing in mind that I want to keep as much of the quality as possible, which output type should I use with avidemux? Thanks.

NB - Sound doesn't work in the avidemux preview.

[poisondeathray]

Use mkv muxer.

The lack of sound might only be missing in the preview , or there might be another version of avidemux that might be better . It can be a bit buggy

For video you want to use x264 . The lower the CRF value, the higher the quality. By the time you reach zero, it will be lossless but several times larger than the original (it's uncompressed, then re-encoded losslessly). If you pick between 18-22 there should be minimal quality loss with decent filesize tradeoff

[lapsang]

OK then. Some follow up questions, if you don't mind:
Which basic profile is the best selection for quality? With or without zero latency?

Thank you!

[poisondeathray]

high10 is 10bit AVC , it is better, higher effeciency, but not compatible with most devices, slower to encode

"high" is the usual 8bit variety. Probably what your source uses. That's what you should probably use

422 and 444 are better chroma subsampling, but if your source is 420, they are not useful

Don't use zero latency

[lapsang]

Ah, that makes perfect sense. I understand the profiles better now and checked the file against VideoSpec.

For an unrelated issue: I have two mkv files that I want to edit together. Not simply merge, though - I want to lift an audio track from one and have it bridge the join into the other (fade in fade out sort of job). I understand two things: one) that I will probably need to convert the mkv files and two) that I will probably need more sophisticated video editing software. Can you recommend the best way I could do this (i.e. best file type, best software)?

You have been of so much help today. Thank you. I will let you know if avidemux is successful (testing now).

[poisondeathray]

For an unrelated issue: I have two mkv files that I want to edit together. Not simply merge, though - I want to lift an audio track from one and have it bridge the join into the other (fade in fade out sort of job). I understand two things: one) that I will probably need to convert the mkv files and two) that I will probably need more sophisticated video editing software. Can you recommend the best way I could do this (i.e. best file type, best software)?

Tough to do on a mac with freeware, especially when you need to fine tune and fiddle with the timing of the audio & fades

If I was doing that task on a mac, I would convert to prores and edit it in FCP / FCPX



There are more paid and freeware alternatives on a PC that can handle it . For example the freeware aviutl could do this quite easily natively as mkv without intermediate steps or conversions

[enim]

on Mac OSX MKVToolnix should work as a rough key-frame cutter.

[ndjamena]

It may not be relevant anymore but, for future reference, there should be a drop down box somewhere on the upper edge of the Handbrake GUI that lets you choose to cut by Chapter, Frames or Seconds. It's been a while since I've used the program, but I assume it's still there. When I was a Handbrake user the seconds option was tied to key frames, but the Frames option could definitely cut at any frame.

[lapsang]

avidemux has worked well, thank you. Better opening it in sudo so it works faster. I don't know about MKVToolnix so I'll stick to what I know works for now.

As for using Handbrake by the frame, I don't know if that works but it seems to be more trouble than it is worth - finding out which the frame is through another software, then manually tapping in the numbers etc..

I will try the other software recommended for my other problem, but for now I consider this case closed! Thank you everyone.