[Bug 700773] gstrtpjpegdepay.c -- index numbering of image components in SOF header off by one

[GStreamer (bugzilla.gnome.org)]

https://bugzilla.gnome.org/show_bug.cgi?id=700773
  GStreamer | gst-plugins-good | git

Wim Taymans <wim.taymans> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEEDINFO
                 CC|                            |wim.taymans at gmail.com

--- Comment #6 from Wim Taymans <wim.taymans at gmail.com> 2013-05-27 12:52:25 UTC ---
> Sample display pipelines
> ------------------------
>
> -- RTP unicast
> $ gst-launch rtpsrc uri=rtp://bla ! rtpjpegdepay ! jpegdec ! xvimagesink
> $ gst-launch rtpsrc uri=rtp://bla ! rtpjpegdepay ! ffdec_mjpeg ! xvimagesink

These pipelines don't make sense, rtspsrc does not have a uri property and the
rtp protocol is not defined in GStreamer.

>
> component table indexing starts at One, not Zero, at least mjpegdec.c of libav
> expects it this way. The standard (ISO/IEC 10918-1) depicts start of indexing
> at One, albeit only graphically. 
> Frame header parameters as stated in Table B.2 allow component index values in
> the range from 0-255 nonetheless. 

They are just IDs, any number is fine, the RFC example code starts from 0, I
see many encoders start from 1. Either way it should work.

> Poor Image Quality
> ------------------
> Apparently luma/chroma quantization coefficients other than defined 
> by ISO/IEC 10918-1 are more suitable.
>
> Did some copy+paste from tables found within the live lib that is employed
> by vlc. These work much better, don't know about their rationale, though.
> see: http://www.live555.com/liveMedia, JPEGVideoRTPSource.cpp

Those tables are already in zigzag order. We store the ISO tables and apply the
zigzag order later. So, this code is equivalent.

Let's start from the start. Could you make available the output (out.gdp) of
the following pipeline:

gst-launch rtspsrc debug=true location=rtsp://bla ! gdppay ! filesink
location=out.gdp

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