[gstreamer-bugs] [Bug 556648] [typefind] detect lossless jpeg

[GStreamer (bugzilla.gnome.org)]

https://bugzilla.gnome.org/show_bug.cgi?id=556648
  GStreamer | gst-plugins-base | git

--- Comment #9 from David Schleef <ds at schleef.org> 2010-12-03 03:28:57 UTC ---
This is from memory...

The only "profile", recommended, but not required by JFIF.  The two hardware
decoders that I have dealt with only decoded baseline:

+      /* SOF0  = 0xc0: baseline

Supported by older versions of IJG libjpeg (6.2):

+       * SOF1  = 0xc1: extended sequential,      huffman
+       * SOF2  = 0xc2: progressive,              huffman
+       * SOF5  = 0xc5: differential sequential,  huffman
+       * SOF6  = 0xc6: differential progressive, huffman
+       * SOF7  = 0xc7: differential lossless,    huffman

Supported by IJG libjpeg 8:

+       * SOF9  = 0xc9: extended sequential,      arithmetic
+       * SOF10 = 0xca: progressive,              arithmetic
+       * SOF13 = 0xcd: differential sequential,  arithmetic
+       * SOF14 = 0xce: differential progressive, arithmetic

Not supported by IJG-jpeg:

+       * SOF11 = 0xcb: lossless,                 arithmetic
+       * SOF15 = 0xcf: differential lossless,    arithmetic
+       * SOF11 = 0xcb: lossless,                 arithmetic
+       * SOF11 = 0xcb: lossless,                 arithmetic


As a rough measure, we have "profiles" libjpeg8 > libjpeg62 > baseline, and a
separate format "lossless".

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