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Hello, I have a very important video file that I am trying to open. I believe it's corrupted, because it isn't detected as an Mp4 file. I've tried opening it in VLC, Windows media, etc with no luck. I tried a program called Remo Repair (Free trial version) and it just told me that it was an unsupported file type. I do have the VLC debug log if that will help at all. If anyone has any advice on how to get this file to play, or even just to get parts of it to play I'd be very grateful. Heck at this point, I would even be grateful if there was a way to open it up and view the individual frames of the video.
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That video repair tool seems to get me further than anything else has. I bought a key, and repaired the file with it. The video seems to be fixed great which is more than I could of hoped for, but at about halfway through the audio seems to be kind of messed up. It seems to have skipped a whole portion of audio which put the rest of the videos auto off track in one video, then in the second one once it gets to within about a minute of the end the audio has about a 10 second repeat loop. Is there anyway to fix the audio with this too? If not, atleast I did manage to save the visual part.
Edit: Both videos have a section where they start repeating the audio near the end. -
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- Aug 2000
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You could try open the mp4 in an editor like avidemux and try cut out the repeat section. But I think avidemux will crash when you try edit it...
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If the mp4 had a section of damaged audio inside, it's possible the program removed it. Since mp4's aren't supposed to have gaps inside in order to mux it properly the program would have had to splice the two sections together, which would leave the audio shorter than the video. As to the end, it depends on what you're playing it with. It's possible the program simply duplicated the last section of audio over and over until it was the same length as the video, or it's possible the player you're using doesn't know how to handle a shortened audio stream and is simply repeating whatever is in it's buffer until the end.
you'd have to take the new file apart to be sure. -
I guess that makes sense, a corrupted section of audio. I guess that would be why it wouldn't play in the first place, then this sliced it out so it would play. I use vlc to play the videos, there is a point when audio just goes off track then it keeps going for a bit, then it begins to start about a 10 second audio loop until the video ends. I'll take a look at that avidemux, is there anyway at all to try to restore that audio or is this the best I'm going to get with what I have?
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I have a DVD... This one actually:
https://forum.videohelp.com/threads/368330-new-to-ripping-DVD-s-have-problems-with-MKV-output-files
And then we go here:
https://github.com/mbunkus/mkvtoolnix/issues/1104
And we end here:
https://forum.videolan.org/viewtopic.php?f=14&t=124278
So, without actually inventing a file to test that is the kind of behaviour I'd expect from VLC when it encounters an early terminating audio stream.
You could try demuxing the original file with mp4box and see what happens, or remuxing with MKVMerge. But since the program you tried is specifically designed to deal with damaged files and the muxing programs aren't I doubt anything will come from trying them. -
Alright. I guess you assumed this would happen, but in Mp4Box, If I try putting it in to demux it, nothing shows up and it just says nothing to demux. In MKV Merge when I try to put it in, I actually get an error message saying
Error: Quicktime/MP4 reader: Have not found any header atoms.
Thank you for the links to your dvd problem, though I'm not sure how to use that to help considering your dvd seemed to not have any errors, just a different issue? Sorry, I am fairly computer literate, i've just never looked indepth into video files before and all this stuff that goes with them.
Would there be anyway to recover that audio, or is just chalked up for irrecoverable? If it makes a difference, the video was recorded with a smartphone haha. Thank everyone for all the help you have offered so far. -
Now that is interesting. If there's no headers then there's nothing to tell the programs what the stream actually is...
I'm wondering if it's an actual MP4 or if it really is just damaged.
mp4box has a diso command that will show the entire contents of the file, see if it's a proper mp4.
As shown in the second thread I link to, some programs will just stick an mp4 label on anything containing h264 and/or aac. -
Well, it was recorded using my smartphone so i honestly have no idea what format it is "supposed" to be, but one of the other videos recorded at the same time is also an mp4 and works good.
How would I use the mp4box thing to check the contents to see if it is a proper mp4? I downloaded the GUI version, and when I insert the file it doesn't show up anything under the demux tab. I apologize for my questions, I just have never done anything technical regarding video files so I am kind of in the dark. I am grateful that you have been working on helping me figure this out though. -
It sounds damaged then, or maybe it's "part 2".
MP4Box is a command line utility from GPAC, any GUI for it is third party and only provides a small subset of MP4Boxes abilities.
MP4Box -info "file.mp4"
MP4Box -diso "file.mp4"
MP4Box -dts "file.mp4"
There are probably more commands that might be useful. -
Hmm so, I got the MP4Box command line version, and I ran the mp4box -info command and diso command. The info one just keeps going on and on saying "Enter new video cache memory in kbytes <current 0d>" and the diso command, that one is just making the console go completely insane with scrolling stuff everywhere. It's going way too fast to read anything and still going about 10 minutes later,
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You're supposed to redirect diso output.
MP4Box -diso "file.mp4" 1>"file.txt" 2>&1
I have no idea what's happening with info, but we already know the file is screwy. -
Hmm. So, I did the diso again with that and am getting that video cache thing with this now. Maybe I'm just missing something obvious and typing in the command wrong? What I am exactly typing is
MP4Box -diso "F:\Files\Desktop\repair these\text.mp4" 1>"F:\Files\Desktop\repair these\diso.txt" 2>&1
I guess I could be entering something wrong, I put the entire file path, I guess it's appropriate that I am posting in the newbie section haha, Thank you for being patient and helping me figure things out. I guess the file is pretty screwy, but the video of it works completely fine it's just the audio is thrown off. Is there anyway to do something like, insert a blank section of audio so it just goes silent for part of the video and makes the rest of the video in sync? -
You'll need to extract it all, mux the audio into a container by itself and cut it. Encode some blank AAC audio, append the three audio segments together and assuming the streams are compatible you'll be done.
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You wouldn't happen to know any sort of guide for that would you? I honestly have no idea what you are talking about. I understand some of it that seems kinda straight forward like encoding blank audio and combining them together, but extracting and muxing a video... Yea I'm lost there.
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You have an mp4box GUI... I should think that would be the easy bit.
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Hmm, I guess I'll give it a try then. Do you have any advice/ tips?
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I've never done it before, but it seems rather straight forward. Silence compresses well, so encoder is irrelevant. You might need something like audacity to pinpoint the exact location to split at...
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Yea, that seems like the most difficult part, finding exactly when to split the audio and the exact time it goes out of sync with the video. Sounds like a project for the weekend though, lots of classwork to fill up the rest of my week. Could you give me a list of software that you suggest I use? I've never even delved into simple video editing before, But this is a pretty important video so I got to take whatever knowledge I can get and throw it at it in the hopes to fix it up as best I can haha.
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Well, I don't normally do this kind of thing, so I'm not sure any audio software does direct stream copy.
If it was me I use mkvmerge to remove the audio from the MP4, get audacity and try to pinpoint the exact moment of the split.
Use MKVMerge to split the file at that point, use neroaacenc to re-encode some PCM silence created by AVISynth and VDub and then append the three components again using MKVMerge, extract the AAC from the MKA and recreate the mp4. It's a pretty crude way of doing it, but that's pretty much how I do everything, take it with a grain of salt. FFMPEG might work in place of MKVMerge, I'm not sure. -
Thank you ndjamena for all the great help and advice. That seems like some pretty straight forward directions, I will take a crack at it over the weekend when I have some actual free time
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