Author Topic: Fixing corrupt files  (Read 180 times)

kentavv

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Fixing corrupt files
« on: December 31, 2018, 03:21:18 AM »
Hi. I have a couple of Chronos videos that will not play. While saving the files, the camera froze, showing a negative frame value, and required a restart to recover. V0.3.1-RC1 software is installed. Both files are 2147483647 bytes long, the maxed out value of 31 bits. Is there anything to try to recover any part of the files? I've tried various online mp4 recovery tools without success. VLC has not been able to fix the files. The SD card is formatted one of EXT formats. Should large files be avoided and known to cause the Chronos to freeze? Thank you and Happy New Year!


skronstein

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Re: Fixing corrupt files
« Reply #1 on: January 03, 2019, 06:11:10 PM »
Hi. I have a couple of Chronos videos that will not play. While saving the files, the camera froze, showing a negative frame value, and required a restart to recover. V0.3.1-RC1 software is installed. Both files are 2147483647 bytes long, the maxed out value of 31 bits. Is there anything to try to recover any part of the files? I've tried various online mp4 recovery tools without success. VLC has not been able to fix the files. The SD card is formatted one of EXT formats. Should large files be avoided and known to cause the Chronos to freeze? Thank you and Happy New Year!
Large files shouldn't be a problem for the Chronos when using any of the EXT filesystems, as they support files over 2gb. Files over 2gb are only a problem on the FAT32 filesystem.

At what point did the camera freeze - at the beginning, middle or end of the save?
At what point did the negative frame number show?
Was the Abort Save button working?
What kind of storage device are you using - SD, USB, or eSATA?
Has this camera and/or storage device successfully saved videos before?
Are you sure that was saving in h264 format, not RAW16 or RAW12? On h264 saves, it shouldn't even be possible to exceed 2GB due to compression, at least with the size of that marked region, which is about 13800 frames long.

foobar

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Re: Fixing corrupt files
« Reply #2 on: January 04, 2019, 03:43:47 PM »
After testing things out a bit, it looks like there is a bug in h.264 file saving that will lead to a crash and file corruption if the MP4 file gets longer than 2GB. This should only be possible when saving very long recordings at very high bitrates, and it should only affect h.264 files. To work around the problem, make sure that the number of frames being saved, divided by the framerate and multiplied by the h.264 bitrate is below 2GB in size.

For example, if you wanted to save 18000 frames at 60fps using the maximum bitrate of 60Mbps would give 18000 frames / 60 fps * 60Mbps = 18Gbits = 2.25GB and would cause the crash to occur.

However, reducing the bitrate to 50Mbps would be fine: 18000 frames / 60fps * 50Mbps = 15Mbit = 1.875GB, and would save without issue.

kentavv

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Re: Fixing corrupt files
« Reply #3 on: January 06, 2019, 04:11:36 AM »
OK, that's great information. This problem indeed occurred at full resolution and high bitrate. Is there any way I might recover any part of the files? I've tried a few freebie tools, including VLC, without success. Thank you

skronstein

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Re: Fixing corrupt files
« Reply #4 on: January 08, 2019, 03:26:21 PM »
This page has a guide and tool that should help to recover your mp4 files: https://www.videohelp.com/software/recover-mp4-to-h264