BUG: strict jpg quality check doesn't work

I'm using two grantec ipcam II as netcams. I access a picture, not a movie. Sometimes the jpg is read incomplete, so there is a big error in the bottom of the picture. Unfortunately this triggers motion detection. I tried netcam_tolerant_check on/off, but in both cases the bad pics appear. (about 5 bad pics per hour average) I also own a 9100a videolan-server which doesn't suffer this problem on the same setup.

Environment

Motion version:	3.2.11
ffmpeg version:	4.9.1
Shared libraries:	ffmpeg
Server OS:	OpenSuse 10.3, kernel 2.6.22

-- JudasHui - 28 Sep 2008

Follow up

I don't see anything interesting in your debug .... you should try to get the return code from those "corrupted" images.

So netcam_tolerant_check option doesn't handle all errors , only some warnings to don't return a fatal error. In your case what do you get ?

- Corrupt end of image ?

- Content-length !!= Image size ?

- Missing jpeg markers, headers ,etc ?

-- AngelCarpintero - 28 Sep 2008

Follow up

I see missing data and the end of some frames , but not sure if because missing data , bad jpeg markers .

I try to find something interesing in your log file , but time of video and log is not matching at all :

Camera : Date: Tue, 30 Sep 2008 17:39:53 GMT

Video : 2008 18:44:53 - 2008 18:46:xx

Probably you sent me a wrong log file ... so please attach your config files and try to send a log file with a video with time synced , NTP in computer

and netcam will help.

A suggestion , grandtec is well know that have broken firmwares , probably you can find some hacked firmware with a lot of fixes.

-- AngelCarpintero - 01 Oct 2008

Follow up

20081008: I did some further tests with some printf within the code.

Although I get messages like "fake EOI inserted" or "Corrupt jpg detected", the error information is not propagated to the next level, so the motion processing triggers unwanted. I must admit that I haven't understood the error propagation mechanism completely, so that I could try some fix on my own.

Follow up

"fake EOI inserted" is not an error , some image miss that marker but are good.

"Corrupt jpg detected" : That's an error ... probably looking at your videos reason is your camera because not sending the complete image so

content-lenght not satisfied ( buggy cam ? )

-- AngelCarpintero - 10 Oct 2008

Follow up

I see "Corrupt Jpeg data: premature end of data segment" and the picture shows that some data was missing in the middle of the jpeg. Unfortunately I didn't manage to get a fixed firmware yet, so my hope is to get motion ignore pictures which were found bad during decompression. Within netcam.c I saw a "FIX ME" which exactly claims a missing check for this kind of errors. Is there a beta awailable where this FIXME is fixed ?

-- JudasHui - 10 Oct 2008

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I can add a patch against trunk version to skip images with critical errors , so they won't produce false detection.

-- AngelCarpintero - 18 Oct 2008

Fix record

Closed , reopen if still problem remains in trunk.

-- AngelCarpintero - 21 Mar 2010