Best Tool for Simple Trimming of MP4 Files?

haravikk

macrumors 65816
Original poster
May 1, 2005
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Quite simply, I've got a number of MP4 files encoded via Handbrake into a nice high-quality but compact H.264 format, however there are some parts I'd like to trim.

In the past I've used MPEG StreamClip, but it doesn't cope with these files at all, either corrupting the start of trimmed clips or not trimming to exactly my selection. I get the impression it's trying to trim the nearest keyframe, rather than creating a new one, but I can't really cut it any other way.

Anyway, I'm wondering what other tools there are out there that can let me just to trim a .mp4 file, ideally without any lengthy re-encoding steps, as I'm happy with the current encoding, I just want to split the file. Ideally I'm looking for something free, command line is fine, or at least fairly cheap, as I'm not doing this professionally or anything.
 

elyah

macrumors member
Feb 17, 2011
36
0
Quite simply, I've got a number of MP4 files encoded via Handbrake into a nice high-quality but compact H.264 format, however there are some parts I'd like to trim.

In the past I've used MPEG StreamClip, but it doesn't cope with these files at all, either corrupting the start of trimmed clips or not trimming to exactly my selection. I get the impression it's trying to trim the nearest keyframe, rather than creating a new one, but I can't really cut it any other way.

Anyway, I'm wondering what other tools there are out there that can let me just to trim a .mp4 file, ideally without any lengthy re-encoding steps, as I'm happy with the current encoding, I just want to split the file. Ideally I'm looking for something free, command line is fine, or at least fairly cheap, as I'm not doing this professionally or anything.
Have you tried
http://www.deepniner.net/mp3trimmer/
 
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haravikk

macrumors 65816
Original poster
May 1, 2005
1,487
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Second for QuickTime and you already own it. Works great and very simple to use.
Which version of Quicktime and which options though? I've tried Quicktime 7 Pro and Quicktime X; while I have to say I'm impressed by the new editing tools in Quicktime X (when were those added?), I can't see a way to keep my file as a .mp4, it just saves as a .mov instead. While I don't mind .mov files exactly, the rest of my video files are .mp4 files, which I prefer anyway for the sake of portability. Quicktime 7 Pro meanwhile doesn't seem to want to save the file as a .mp4 without re-encoding it; I assume the .mov format will function as Quicktime X does, but again I was hoping to just use .mp4.

I gave avidemux for Mac a go; it's interface is almost indescribably bad, but it seems to do the trick, though similarly to MPEGStreamClip it's limited to only cutting files on key-frames, though it's a lot better at showing you where these are and doesn't produce any weird visual issues.
 

firedept

macrumors 603
Jul 8, 2011
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Somewhere!
Which version of Quicktime and which options though? I've tried Quicktime 7 Pro and Quicktime X; while I have to say I'm impressed by the new editing tools in Quicktime X (when were those added?), I can't see a way to keep my file as a .mp4, it just saves as a .mov instead. While I don't mind .mov files exactly, the rest of my video files are .mp4 files, which I prefer anyway for the sake of portability. Quicktime 7 Pro meanwhile doesn't seem to want to save the file as a .mp4 without re-encoding it; I assume the .mov format will function as Quicktime X does, but again I was hoping to just use .mp4.

I gave avidemux for Mac a go; it's interface is almost indescribably bad, but it seems to do the trick, though similarly to MPEGStreamClip it's limited to only cutting files on key-frames, though it's a lot better at showing you where these are and doesn't produce any weird visual issues.
If you have QuickTime 7 Pro, when you are done trimming the clip, instead of saving the clip, export it and then save it as an mp4. I have attached a screenshot to show you the export setting. Ignore that it states movie to MPEG-4. You are just exporting an mp4 to an mp4.
 

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Fishrrman

macrumors P6
Feb 20, 2009
17,398
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firedept wrote above:
[[ If you have QuickTime 7 Pro, when you are done trimming the clip, instead of saving the clip, export it and then save it as an mp4. I have attached a screenshot to show you the export setting. Ignore that it states movie to MPEG-4. You are just exporting an mp4 to an mp4. ]]

During the "export" process, does QuickTime "re-process" the mp4 file? By that, I mean does it first de-compress the file, and then re-compress the new, exported clipping?

Or -- does QT do all this without decompressing/re-compressing?

I'm wondering if there is some additional "lossiness" going on in the background, i.e., some content quality lost as a part of the re-compression process.

What makes MP3Trimmer excellent for working with mp3 files is that it does its magic "losslessly" by working with the mp3 file "natively", without re-compression.
 

haravikk

macrumors 65816
Original poster
May 1, 2005
1,487
19
If you have QuickTime 7 Pro, when you are done trimming the clip, instead of saving the clip, export it and then save it as an mp4. I have attached a screenshot to show you the export setting. Ignore that it states movie to MPEG-4. You are just exporting an mp4 to an mp4.
Ah, thanks for the help; I found the Passthrough options for Video and Audio in the options menu when exporting, this let me re-save the trimmed .mp4 without any apparent re-encoding; it also seems able to trim between key-frames, which is great.

I just hope Quicktime 7 Pro keeps working for a while to come then; the trim tools in Quicktime X are nice, but its export options suck badly, and iMovie isn't much better either which is a shame.
 

sonicblue83

macrumors member
Dec 30, 2008
59
1
Yep I use quicktime for this too.
Hi everybody,

I'm also looking for a good program to trim mp4 without reenconding. I tried different ones including Quicktime 7 but all of them had the same problem. If I trim something in the middle of the file (commercials for example) then audio gets out of sync over time.

Does anybody know a programm which trims mp4 without audio getting out of sync?