Please help the lame user

[popov654]

Hello everybody! Happy New Year)
I have a seious problem. We had a conference at the university two weeks ago, and I recorded it on the web-camera with the help of VLC Player. I set the output format to video h.264, audio aac, container MP4. The event lasted about 4 hours.
When it was over, I pressed Stop and closed the application. As I learned afterwards, I had to wait for about 1 minute for the writing process to stop actually (perhaps because of some buffer). But then I didn't know about it and closed the program, it didn't show any message. And the highly valuable file remained unfinished, without headers and probably without the ending. The ending is not so important, but without headers I cannot open it with any program!

So, I decided to ask for your help, because no one knows the format and writing algorithm better than you. Could you help me some way to repair my video? Or just tell about the headers that VLC writes in MP4 and their purpose?

I opened the recorded file in WinHEX, opened another file that is longer (about 6 hours) and tried to "transplant" the missing beginning from the normal video. The file opened correctly in most players, the length was equal to the length of the normal file, but all that I could see was the black screen and absolute silence. I guess that there must be some matrix that helps the player to read audio and video fragments correctly. Could you help me to reconstruct it? Or advise some program that can do it automatically?

[Sébastien Escudier]

I guess that there must be some matrix that helps the player to read audio and video fragments correctly. Could you help me to reconstruct it? Or advise some program that can do it automatically?

Yes this is the case.

You could try to read your file as raw h264, but I don't know if it will work...

[popov654]

How can I do it? Sorry, I really don't understand much in it

[popov654]

And yes, what about audio track? Can it be extracted? Or it was lost with the beginning?

[popov654]

Good news! For the file that I got after editing in WinHEX Windows has generated a preview thumbnail, and, which is the most significant fact, I recognize the beginning of the record!
At least it is the proof that the file is not "garbage" if I decide to use the service of some data rescue company...

[popov654]

Please, somebody help me...

[popov654]

Ok, sorry, I know nobody will help me in recovering my data for free. I probably should go and visit some recovery service. Let's set the question a bit another way: could you analyse my file and tell me what exactly was lost (part of the video, sound, just service information like headers)? And if it is possible to recover anything ("guess" the missing values in case of lost headers, for example). You wrote the code of the encoders, right? So nobody knows the output file format as well as you. That's why I came here. If it is not difficult for you, view my file in WinHEX and just explain me what each part means.

You know, there is such block in the second half of the normal file:
Quick Time 6.0 or greater...#©enc....vlc 1.1.0 stream output....wide.
and then goes lots of data, probably video stream.

And my broken file begins like that:
....ftypisom....mp41avc1qt ....wide.
and then goes lots of data. Is that recoverable? Is the sound recorded in the section after "wide" or it was lost?

I can provide the full file if needed, but it is about 170 Mb.