Transcoding file with mp4 container to h263 encoding fails

[primkey7607]

When using AddVideo to load an mp4 file and transcode it into h263, I get the error:

[Exception] OpenFailed at src/vcl/Video.cc:383 on the server side, and {u'info': u'Internal Server Error: VCL Exception at QH\n', u'status': -1} on the client side

This seems to happen regardless of the video being transcoded, as long as the video is an mp4 file, and it is being transcoded to h263.

[luisremis]

Apparently, h.263 implementation in OpenCV/ffmpeg (u263) expects the frame size to be of a particular size:

OpenCV: FFMPEG: tag 0x33363255/'U263' is not supported with codec id 5 and format 'mp4 / MP4 (MPEG-4 Part 14)' [h263 @ 0x7f324082fda0] The specified picture size of 720x528 is not valid for the H.263 codec. Valid sizes are 128x96, 176x144, 352x288, 704x576, and 1408x1152. Try H.263+. Could not open codec 'h263': Unspecified error

I tried setting the size to (720x528, using the resize operation in VDMS), and it almost worked. I got another error instead:

OpenCV: FFMPEG: tag 0x33363255/'U263' is not supported with codec id 5 and format 'mp4 / MP4 (MPEG-4 Part 14)' [mp4 @ 0x7fe886a30e60] Could not find tag for codec h263 in stream #0, codec not currently supported in container

It seems OpenCV/ffmpeg do not support using h263 coded videos using mp4 container.

Then I tried h263, resizing, and changing the container to “avi” and the transcoding worked fine.

We can explore and see whether we can add a different h263 implementation in OpenCV that allows any size and mp4 container.

[luisremis]

@mahircg Something interesting to look at at some point.

[ifadams]

@cwlacewe closing as stale.