[Matroska-users] Problem playing recorded MJPEG with high resolution

Ivan Kowalenko ivan.kowalenko at gmail.com
Sun Jan 29 18:29:37 CET 2012


I'm not sure most graphics cards are designed for accelerating MJPEG
decoding, since mostly what I've seen is focused on H.264 decoding (to
assist with commercially distributed HD material, such as iTunes purchases
and BluRay playback).

I can confirm that VLC will immediately crash upon opening the file in
version 1.1.12 in Mac OS X 10.6.8 (32-bit mode). I also ran a test with
mplayer to see if I could get some more detailed information, and as luck
would have it, it did!

Ayanami:Downloads kichigai$ mplayer Cam564-20120124-124827.mkv
> MPlayer SVN-r32528-4.2.1 (C) 2000-2010 MPlayer Team
> Can't init Apple Remote.
>
> Playing Cam564-20120124-124827.mkv.
> libavformat file format detected.
> [matroska,webm @ 0x10180ee00] Unknown entry 0xFF
> [matroska,webm @ 0x10180ee00] Unknown entry 0x656E
> [matroska,webm @ 0x10180ee00] Unknown entry 0x4273
> [matroska,webm @ 0x10180ee00] Unknown entry 0x67AD
> [matroska,webm @ 0x10180ee00] Read error at pos. 1550586 (0x17a8fa)
> [matroska,webm @ 0x10180ee00] Invalid stream 1 or size 3
> [matroska,webm @ 0x10180ee00] Estimating duration from bitrate, this may
> be inaccurate
> [lavf] stream 0: video (mjpeg), -vid 0, video
> VIDEO:  [MJPG]  1600x1200  0bpp  10.000 fps    0.0 kbps ( 0.0 kbyte/s)
> ==========================================================================
> Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
> [mjpeg @ 0x100a1b740]mjpeg: using external huffman table
> Selected video codec: [ffmjpeg] vfm: ffmpeg (FFmpeg MJPEG)
> ==========================================================================
> Audio: no sound
> Starting playback...
> Could not find matching colorspace - retrying with -vf scale...
> Opening video filter: [scale]
> Movie-Aspect is 1.33:1 - prescaling to correct movie aspect.
> [swscaler @ 0x100a23920]using unscaled yuv422p -> yuyv422 special converter
> VO: [corevideo] 1600x1200 => 1600x1200 Packed YUY2
> [ASPECT] Warning: No suitable new res found!
> V:   0.0   0/  0 ??% ??% ??,?% 0 0
> [matroska,webm @ 0x100a18e60]Read error at pos. 1550587 (0x17a8fb)
> V:   0.0   0/  0 ??% ??% ??,?% 0 0
>
>
> Exiting... (End of file)
> Ayanami:Downloads kichigai$
>
 Notice how to says it's attempting to decode the video at a resolution of
1600×1200. I suspect that this is where your problem lies, and that
somewhere between your source video and mkvmerge is a mismatch in detected
resolutions. Indeed, this is what mkvinfo had to say:

> + EBML head
> |+ Doc type: matroska
> |+ Doc type version: 2
> |+ Doc type read version: 2
> + Segment, size 10146941
> |+ Seek head (subentries will be skipped)
> |+ Segment information
> | + Timecode scale: 1000000
> | + Duration: 7.230s (00:00:07.230)
> | + Date: Tue Jan 24 18:48:34 2012 UTC
> | + Muxing application: dsj_MKVSink (dsj 0_8_64)
> | + Writing application: dsj_MKVSink (dsj 0_8_64)
> |+ Segment tracks
> | + A track
> |  + Track number: 1
> |  + Track type: video
> |  + Track UID: 1185106944
> |  + Default duration: 100.000ms (10.000 fps for a video track)
> |  + Video track
> |   + Pixel width: 1600
> |   + Pixel height: 1200
> |   + Frame rate: 10
> |  + Codec ID: V_MS/VFW/FOURCC
> |  + CodecPrivate, length 46 (FourCC: MJPG, 0x47504a4d)
> |  + Name: video
> |+ Cluster
>
Try specifying the video resolution in your mkvmerge command and see if
that fixes the problem. --display-dimensions might fix the problem, but no
promises if it's interpreting the video data to be encoded at the wrong
resolution. I would also check your source file's container. Perhaps you
can tweak that to pass the right information.

----------------------------------------------------
Ivan Kowalenko
w: http://ivankowalenko.com
e: ivan at ivankowalenko.com




On Wed, Jan 25, 2012 at 1:05 PM, David R Robison <
drrobison at openroadsconsulting.com> wrote:

>  We have a nVidia graphics card. I'm sure our hardware is sufficient as we
> do a lot of software video decoding. vlc Plays the first frame then
> crashes. David
>
>
> On 1/25/2012 2:01 PM, Ivan Kowalenko wrote:
>
> Try VLC. It may behave a little better. What are you running for hardware?
> It could just be overwhelming.
>
> ----------------------------------------------------
> Ivan Kowalenko
> w: http://ivankowalenko.com
> e: ivan at ivankowalenko.com
> p: 856-270-6049
> On Jan 25, 2012 11:04 AM, "David R Robison" <
> drrobison at openroadsconsulting.com> wrote:
>
>
> _______________________________________________
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>
> --
>
> David R Robison
> Open Roads Consulting, Inc.
> 103 Watson Road, Chesapeake, VA 23320
> phone: (757) 546-3401
> e-mail: drrobison at openroadsconsulting.com
> web: http://openroadsconsulting.com
> blog: http://therobe.blogspot.com
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>
>
>
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