Help with corrupted CamStudio AVI

[videohelpneeded]

Hello, I have a 4GB video I recorded with CamStudio. Windows Media Player will not play it. Here are the things I've tried to fix it:

Played with VLC: It spends some time repairing it. It says the index file is broken or missing. When I tell it to build the index, it successfully plays the last 1:03 of the video. I have the audio of the video recorded separately in a wav file. It's 33:03 so I want the video ideally to be that long, or at least close to it.

Media Info has the following information:
Format : AVI
Format/Info : Audio Video Interleave
Format settings : BitmapInfoHeader
File size : 4.00 GiB
Duration : 33 min 24 s
Overall bit rate : 17.1 Mb/s
Frame rate : 20.000 FPS

Video
ID : 0
Format : RGB
Codec ID : 0x00000000
Codec ID/Info : Basic Windows bitmap format. 1, 4 and 8 bpp versions are palettised. 16, 24 and 32bpp contain raw RGB samples
Duration : 33 min 24 s
Bit rate : 16.5 Mb/s
Width : 1 920 pixels
Height : 1 008 pixels
Display aspect ratio : 1.905
Frame rate : 20.000 FPS
Color space : RGB
Bit depth : 8 bits
Bits/(Pixel*Frame) : 0.425
Stream size : 3.84 GiB (96%)

I opened it in Virtual Dub and it complains about the missing index as well. It has a few warnings and ultimately plays about 14 seconds of video. Interestingly, it's a different 14 seconds.

Recently I found there's a Virtual Dub 2. I tried opening it there. The good news is that it shows it as 33:03. The bad news is it only seems to display one frame, and it's messed up - colors are wrong and it's not centered right. I then told it to ignore the index file and keyframes and it opened correctly - although once again only about 14 seconds of the end. Same as VD1.


[Attachment 74720 - Click to enlarge]

I've tried doing this AVI repair but it doesn't seem to work. https://camstudio.org/forum/discussion/1430/repair-corrupt-camstudio-files-when-camstu...recording.html

The "repair OK" happens but Virtual Dub opens it and it's just a black square.

Also tried Avidemux and GOM Player. They can't open the file.


Does anyone have any ideas?

[Swedaniel]

DivFix++ v.0.34 can help with this! I tested it and it was working! The program is avalible as 32bit and 64bit portable, basicly just unpack the zip file and launch the program, then drag and drop the avi video file onto the program and click Fix. It is possible to select to 'Keep original file' and it will create an new, fixed, copy of the video. The program is free and does not leave any watermarks!

Edit: If the index gets fixed and is able to play in some video players, but not in Windows Media Player you might need an codec to be able to play the video... You could allso convert the video to an other format (or convert into an avi video with an codec supported by Windows Media Player). Sometimes Index Errors get fixed when converting the video.

Edit 2: When using some recorder programs they can give index error on the first recording after changing settings for the recording.

[ProWo]

You can try to open it with clever FFmpeg-GUI.
The codec is supported.
If the video loads, click main, click encode video stream, click keep size, leave all settings as the are and click encode.
If finished, you have a new mkv file that can be played with any player.

[videohelpneeded]

DivFix++ v.0.34 can help with this! I tested it and it was working! The program is avalible as 32bit and 64bit portable, basicly just unpack the zip file and launch the program, then drag and drop the avi video file onto the program and click Fix. It is possible to select to 'Keep original file' and it will create an new, fixed, copy of the video. The program is free and does not leave any watermarks!

Hello, thank you for the answer. The file gave me "seek error on file" and "error 87: the parameter is incorrect." It also said "can't find current position in file."

I tried doing it with "Recover from Key Frames" on and off, in both cases the resulting file was unplayable.

I tried the "strip index" button and it said this: "Error: File cannot truncate at -990587656
Error occured at striping index."

[videohelpneeded]

You can try to open it with clever FFmpeg-GUI.
The codec is supported.
If the video loads, click main, click encode video stream, click keep size, leave all settings as the are and click encode.
If finished, you have a new mkv file that can be played with any player.

Hi, thanks for the answer.

It loaded and I encoded, but the resulting MKV file was very small and played for only like half a second.

I also tried converting it with Handbrake, the resulting file was 150KB and seemingly 1 frame long.

[ProWo]

You can try to open it with clever FFmpeg-GUI.
The codec is supported.
If the video loads, click main, click encode video stream, click keep size, leave all settings as the are and click encode.
If finished, you have a new mkv file that can be played with any player.

Hi, thanks for the answer.

It loaded and I encoded, but the resulting MKV file was very small and played for only like half a second.

I also tried converting it with Handbrake, the resulting file was 150KB and seemingly 1 frame long.

Upload the avi somewhere and post the link here, so we can take a look.

[videohelpneeded]

I appreciate the offer but honestly, it's not a video I would want anyone else to have. I would be willing to do anything with any program you recommended but I can't share it, especially on a public forum. I hope you understand. Thanks.

The problem was with CamStudio. Apparently if you recorded too long it would crash when attempting to save. This was a known issue. What I salvaged was the temporary files it created. That's why it's exactly 4GB, it could only save 4GB files maximum iirc. At the end I assume it writes the index/header, only these were never written.

This link describes the situation well:

https://camstudio.org/forum/discussion/1430/repair-corrupt-camstudio-files-when-camstu...recording.html

"Complete AVI files contain a header, a short section of the file which describes the video properties like the codec, resolution, etc. The problem is that the AVI headers are written at the end of the capturing session, so if Camstudio crashes, no header gets written, and this is the reason it cannot be opened in any media player. However, *the data is still there!* We just need to recover it."

The problem is their AVI repair tool doesn't seem to work for me. Maybe I need to make sure the resolution/codec matches better when creating a new AVI file to use for the repair process.

[videohelpneeded]

"Codec ID : 0x00000000
Codec ID/Info : Basic Windows bitmap format. 1, 4 and 8 bpp versions are palettised. 16, 24 and 32bpp contain raw RGB samples"

Does someone know what this codec is? I've tried googling it but I can't find it. Does it go by another name?

EDIT: Downloading the K Lite codec pack made a weirdly colored version appear as a thumbnail for my file, but it did not play any better.

[ProWo]

The last ressort:
Open your video in a hex editor.
If you see all zeros, the file is gone.

[ivanb]

@videohelpneeded, if you open your file with this tool: https://media-analyzer.pro , do you see any headers there? Could you send a screenshot if there are some?

[videohelpneeded]

@videohelpneeded, if you open your file with this tool: https://media-analyzer.pro , do you see any headers there? Could you send a screenshot if there are some?

Here is what it gave me:

0000000000RIFF Header #0
000000000c'hdrl' AVI Header List #1
0000000018'avih' AVI Main Header #2
0000000058'strl' AVI Stream List #3
0000000064'strh' AVI Stream Header #4
ckID 'strh' (hex 73 74 72 68)
ckSize 56 (0x38)
fccType 'vids' (hex 76 69 64 73)
fccHandler '\00\00\00\00' (hex 0 0 0 0)
dwFlags 0
wPriority 0
wLanguage 0
dwInitialFrames 0
dwScale 1
dwRate 20 (0x14)
dwStart 0
dwLength 40095 (0x9C9F)
dwSuggestedBufferSize 5806080 (0x589800)
dwQuality 0
dwSampleSize 0
rcFrame
left 0
top 0
right 1920 (0x780)
bottom 1008 (0x3F0)
00000000a4'strf' AVI Video Format #5
00000000d4'JUNK' Garbage #6
00000007f4'movi' AVI Movie Data #7
0000000800'Kr<K' AVI Chunk #8
00724b4579RIFF Chunk Alignment #9
00724b457a'\00\00\00\00' AVI Chunk #10
00c4f4d4f8'+:\8' AVI Chunk #11

[videohelpneeded]

The last ressort:
Open your video in a hex editor.
If you see all zeros, the file is gone.

I opened it in Virtual Dub's hex editor. There are some chunks that are just zeroes, and some that are just FF FF FF. But the majority of it looks normal to me (a blend of letters and numbers.) I would say at least half if not more is normal, but yes, there are big chunks of 00 and FF

[ivanb]

Here is what it gave me

The beginning looks good, but

0000000800'Kr<K' AVI Chunk #8

is corrupted already.

Could you copy the contents of "00000000a4'strf' AVI Video Format " header here?

If you look at the file in HEX editor, can you spot at least a few occurrences of "00dc" or "00db" character groups? (see example in screenshot attached)


[Attachment 74894 - Click to enlarge]

[videohelpneeded]

Could you copy the contents of "00000000a4'strf' AVI Video Format " header here?

I'm not entirely sure how to find it. Is this it?

[Attachment 74895 - Click to enlarge]

If you look at the file in HEX editor, can you spot at least a few occurrences of "00dc" or "00db" character groups? (see example in screenshot attached)

Yeah, there are a few. Here are some.


[Attachment 74896 - Click to enlarge]

[Attachment 74897 - Click to enlarge]

[Attachment 74898 - Click to enlarge]

[Attachment 74899 - Click to enlarge]

[davexnet]

I would say stop using CamStudio and switch to OBS

[ivanb]

ok, we need some surgery here.

Step 1. At first we need a donor. Could you record (or maybe you have some already) the good file with exactly the same settings (dimensions, codec parameters if any)?. Better if it will be at least several minutes.

Step 2. You need to find the first occurrence of bytes "30 30 64 62 00 98 58 00" in your corrupted file - that would be a start of the first good frame. You need to write down the offset of such occurrence. Let it be, for example, 0x636D28, or just X

Step 3. Make a backup copy of your corrupted file, just in case

Step 4. You need to take first X bytes from your donor, copy them over to the beginning of your corrupted file and save it

If you're lucky, after this operation you will have the video that can be played back and which will contain the frames from your corrupted file. If you get that - great. After that we may need to modify the duration of the file. That would be again a bit of surgery, but simpler one. I'll give the instructions once your first operation succeeds.

[videohelpneeded]

Step 1. At first we need a donor. Could you record (or maybe you have some already) the good file with exactly the same settings (dimensions, codec parameters if any)?. Better if it will be at least several minutes.

I can't remember which codec I used which is why I was asking about the "bitmap" codec that was reported by media info. My video was originally done on a different computer, which I can probably find if that matters. I'm using CamStudio and it gives me as options Cinepak codec, Microsoft Video 1, and two instances of Intel IYUV codec. I was thinking probably Cinepak since that's the default but I'd like to be sure.

Step 2. You need to find the first occurrence of bytes "30 30 64 62 00 98 58 00" in your corrupted file - that would be a start of the first good frame. You need to write down the offset of such occurrence. Let it be, for example, 0x636D28, or just X

OK, I found it.

Step 3. Make a backup copy of your corrupted file, just in case

I did this.

Step 4. You need to take first X bytes from your donor, copy them over to the beginning of your corrupted file and save it

I was using Virtual Dub's hex editor, not sure if I can copy it using that. But I plan to do it with Notepad++ unless you have a better recommendation.

Once again, thanks for all your help.

[ivanb]

I can't remember which codec

Can you make a screenshot of what analyzer shows when you open "AVI Video Format" chunk of the corrupted file?

which I can probably find if that matters

If it's not a big problem, it's better to use the same PC, hoping that all settings remained untouched there

But I plan to do it with Notepad++ unless you have a better recommendation.

On Windows HxD is quite nice, WinHex is a legend, didn't try Notepad++ to edit binary files

[videohelpneeded]

Here it is:

[ivanb]

I'm using CamStudio and it gives me as options Cinepak codec, Microsoft Video 1, and two instances of Intel IYUV codec.

"Microsoft Video 1" is probably the best option to try for a start. Record something and then check if the values in 'strf' chunk of old/new files match

[videohelpneeded]

Step 2. You need to find the first occurrence of bytes "30 30 64 62 00 98 58 00" in your corrupted file - that would be a start of the first good frame. You need to write down the offset of such occurrence. Let it be, for example, 0x636D28, or just X

OK, I downloaded HxD and tried to find that string - both with spaces and without - and couldn't find it. I could find 30 30 but not anything with 30 30 64. Sorry for the delay.

[ivanb]

> I could find 30 30 but not anything with 30 30 64

There were at least some such occurrences in your previous screenshots (e.g. https://forum.videohelp.com/attachment.php?attachmentid=74899). I meant hex bytes sequence, not characters

[richardpl]

Not possible unless some knowledgeable person baby steps you into whole process.