Video processing issues

[1553690132]

我在使用 FeatureExtraction.exe -f "D:\Program Files\project\dataset\cohface\2\0\data.avi" -out_dir "D:\Program Files\project\dataset\cohface\2\0" -2Dfp 命令处理cohface数据集时出现了：[mpeg4 @ 000001c9dc667f40] slice end not reached but screenspace end (69 left 7CF32F, score= -1196) 请问是什么原因？

[brmarkus]

Can you provide more details, please? Can you reproduce the behavior when using other video files? Can you try with other videos like from "https://github.com/TadasBaltrusaitis/OpenFace/tree/master/samples"?

I see similar posts when searching with a search-engine - and some point to the library libavcodec: log message created by libavcodec, but very much depends on the video file.
Was your video file recorded from a live-stream and it ends suddenly with incomplete frames and references to missing future frames?

Can you try to playback the file with other players (ffmpeg, ffplay, gstreamer, VLC, etc) and check for logs/warnings/errors?

With your command line, is nothing processed, no output stored? Or do you see results, and then "only" the log message at the end?

[1553690132]

This is the file I have processed, it looks like there are no errors. data.csv
The video can be played normally, this is the Cohface dataset:

[1553690132]

There is indeed no such issue when processing other video data, such as UBFC-RPPG and UBFC Phys.

[brmarkus]

From your attached DATA.CSV file it looks like 1205 frames could be processed. Do you expect more frames? (you might need to check with a player or a tool to see how many frames the video file contains)

Do you see the log message at the beginning after starting FeatureExtraction.exe, or at the end?

From the log message it looks like it occurs at the end - and might just be a log message and not an error.

Can you try a "console player" like ffmpeg, ffplay or gstreamer (a console player started in the console, which prints logs to the console) (VLC-player has a menu "Tools|Messages"to show codec log messages) ?

[1553690132]

My video is 1 minute and the frame rate is 20Hz. That's correct, but what does the error he reported to me mean?[mpeg4 @ 000001c9dc667f40] slice end not returned but screenspace end (69 left 7CF32F, Score= -1196)
Are you saying this is just a log and not an error?

[brmarkus]

So you are not missing frames?
The tool is not aborting the process and ignoring frames?

I just used a search-engine (Google) and searched for

mpeg4 @ 000001c9dc667f40] slice end not reached but screenspace end (69 left 7CF32F, score= -1196)

You can find other people reporting this log message (but with different numbers of course), with links to software video codecs (decoder, transcoder), caused by a library libavcodec, used by players like FFMPEG, GSTREAMER.

Someone recorded the video and maybe just aborted the video-recoder (Ctrl-C?), so the video file ends with incomplete video frames. And depending on values like GOP and depending on the video elementary stream format and codec-settings there are different frames like I, R, P frames, which could even reference each other - and which are then just missing, incorrect, incomplete.

From the log messages (there are percent-values counting 0%, 10%, 20%... 80% 90% 100%) it looks like the tool is continuing regardless of the log message - but not sure, the log message could be asynchronous&bufferend and log messages could overlap.
I, me, personally, would say, yes, its just a log message.

But be warned... if you are processing a very critical video stream and your "customers" does not allow the software to miss a single frame (maybe safety-critical?), then you might need to have a closer look into the video decoder and error-recovery and things like that (and/or using another codec, maybe even using GPU for decoding, using a different video-format with better, higher, lower compression, h.265 instead of h.264? AV1 instead of h.265, lower/higher bitrate, lower-higher framerate, better shielded camera/network cables, etc).