Bug#863663: libgstreamer1.0-0: plays MJPEG AVI files (and possibly other formats) at degraded quality

[Francesco Poli]

On Tue, 30 May 2017 10:18:57 +0300 Sebastian Dröge wrote:

[...]
> Can you provide a sample file and screenshots from both applications
> for comparison? Thanks!

Hello!

First of all, thanks a lot for your prompt reaction.

I have just prepared a test case: you should find it attached to this
message.
The compressed tar archive includes a small Fortran program that
generates the sample data, a ParaView state file, and the resulting AVI
video[^NOTE].

The attached screenshots are obtained with:

  $ mpv wave_anim.avi

and

  $ gst-launch-1.0 filesrc location=wave_anim.avi \! decodebin \! autovideosink

respectively.

The image rendering quality looks significantly different: GStreamer
seems to render the video at degraded quality, with respect to mpv.
ffplay also renders the video at a quality nearly identical to mpv...

I hope this test case may help in pinpointing the issue.
Please let me know.

Thanks for your time!


[^NOTE]: If someone wants to recreate the AVI file, the steps are:
         0) compile gen_waveplot3d.f (with gfortran or another
            Fortran compiler)
         1) run the executable
         2) start ParaView
            $ paraview --state=wave_anim.pvsm
         3) select Save Animation ... from the File menu
         4) set Frame Rate 5 fps,
                1 Frame / timestep,
                Resolution 996 x 784,
                Timestep range 0 ÷ 30,
                No Stereo,
                [x] Compression
         5) Save Animation to "wave_anim.avi"

-- 
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 There's not a second to spare! To the laboratory!
..................................................... Francesco Poli .
 GnuPG key fpr == CA01 1147 9CD2 EFDF FB82  3925 3E1C 27E1 1F69 BFFE
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