Can a avi video file that's to small be fixed ?

[videonewbie]

Hello,

Let me explain i have a security camera in my house it supports wifi so you can connect it to a smartphone one day i received a push notification from the app of the camera about motion detection i tryed to watch live but it didn't work well due to being in an area with a bad mobile signal when i got home i check the camera but the involved avi video is only 216 kilobyte in size probably this issue is caused because i tryed to watch live with a bad connection i still have that video wondering if this can be fixed ? i guess i losed the stuff that happened in that video .

[jagabo]

216 KB is not very big. Whether it can be fixed or not depends on what's wrong with it, what codecs are used, etc. Try posting a MediaInfo report on the contents of the video and another from the same camera.

[videonewbie]

Hello,

I have read here about software like DivFix++ , virtualdub , virtualdubmod etc and managed to fix the avi index .The filesize increased to 906 kb (still small for a video) i did this by rekeying the videostream in virtualdub when i try to play this video there is only sound the screen stays black

The video is encoded with H264 and there is a difference in the two attachments the video that is fine has more data displayed in it's mediainfo

Mediainfo software says the involved avi video is truncated whatever that means.

[jagabo]

It looks like you don't have much more than the AVI header (at the start of the file). The two videos are both 3 minutes long but the good one is 100x bigger. You can try using VirtualDub's Hex Editor (Tools -> Hex Editor) and its RIFF Chunk Tree viewer (Edit -> Riff Chunk Tree) to see there are any video packets (sample below). I suspect not.


[Attachment 49085 - Click to enlarge]

On the left is the RIFF Chunk Tree. In the bottom half of the list are a few of the audio and video chunks. Your 3 minute, 11 fps video should have thousands of chunks.

Given the the file is so severely truncated you won't be able to recover much. Imagine a 300 page book where you have only the first 3 pages. You may have the title page and the table of contents. There's no way you can restore the body of the book from that.

[videonewbie]

Hello,

That menuitem in the virtualdub hex editor is greyed out i do have another hex editor and will check that stuff for a good video and a bad video just to learn how this stuff works i guess you're right that bad video cannot be recovered .

Thank ou for explaining though .

[jagabo]

That menuitem in the virtualdub hex editor is greyed out

You must open a file (in the Hex Editor) first.

[videonewbie]

Hello,

When i try to open the bad avi in virtualdub hex editor and press ctrl + r it says invalid LIST/RIFF chunk

[JVRaines]

That's because the header says the file is supposed to be much longer than what you actually have. I would guess your file is trashed.

[jagabo]

That means the file is too damaged for VirtualDub's RIFF Chuck Tree tool to analyze. You can try parsing/searching the hex data manually (you can see the RIFF chunks, identified by fourcc codes, in the image I posted). The video chunks are identified by the fourcc (plain text) "00dc", audio chunks by "01wb".

You might try playing the video with VLC. It can play truncated AVI files better than some others. You might see a few seconds of video. If you do, you might be able to use its conversion tool to extract those frames and mux them into another file for easier access in other tools.

[videonewbie]

Hello,

With vlc player the screen is not black but there is no video either it just displays a purple / pink screen the whole video .

[videonewbie]

Hello,

Now i receive another in virtualdub see the screenshot.

[jagabo]

Did you try searching for video chunks with the hex editor? Did you find any? If you want to upload a copy I'll take a look at it.

[videonewbie]

Did you try searching for video chunks with the hex editor? Did you find any? If you want to upload a copy I'll take a look at it.

I did i found several "00dc" and "01wb" using that virtualdub hex editor ctrl + r but it says there is junk i've read here that software called avimux-gui can clean up junk but that software doesn't work on Windows 10.

[jagabo]

Junk chunks are normal. Pretty much every AVI file has them. They are used as padding to align later data. Notice how the movi chunk immediately after it starts at address 00001000. But the video chunks is very small, only about 4000 bytes (1035 hex), very small for a 1080p video. I suspect there's nothing there.

[videonewbie]

OK time to give up no biggie anyway thanks for your help .