Re: OT: Why? Using eeePC as digital photo frame with server push...

On a sunny day (Thu, 04 Sep 2008 21:43:58 +0100) it happened Martin Brown
<|||newspam|||@nezumi.demon.co.uk> wrote in
<da2b8$48c0488a$11340@xxxxxxxxxxxxxxxxx>:

One version of the Fuji Frontier photolab quality colour printer
firmware had a curious fault that meant it worked perfectly with any
24bit YCC encoded JPEG but gave a completely surreal random false colour
map to pure single channel monochrome 8bit JPEGs (consistent but nothing
like an 8 bit greyscale). The effect was highly amusing whilst it lasted.

I suspect at least one JPEG codec still has a quirk when faced with
unusually encoded images. The PaintShopPro encoder from v8 onwards is
actually terminally broken in chroma subsampling but hardly anyone has
noticed. The IJG codec is a pretty good reference JPEG implementation.

In a first test I managed to get some pics working in ffmpeg by using
Imagemagick's 'convert' to first convert from jpg to ppm (RGB format),
and then from ppm to jpg again... but it still got into problems with some BW.
I used libjpeg.so.62.0.0 for my own program, and simply added
code for cinfo.out_color_space == 1, late last night, so simple, worked
to my amazement.
Now no more need to pre-process via 'convert' other then getting all pics the
same size and screen filling on the target screen, and it does create
predictable formats, keeps aspect right.
It is nice to have all the open source libs, and manuals.
There must a be lot of desperate crying users out there trying to do what
the soft does not do :-), and being unable to do anything about it.
For MS windows I mean....
They then usually get recommended an other $$$$$ application.....
In Linux the imagemagick program suite is pretty good for most picture
manipulations, and this is one of the first times ffmpeg failed on me.

.

Relevant Pages

  • EncoderTransformation ignored, no errors produced.
    ... I would also like to use the EncoderTransformation encoder parameter ... and writes out two jpeg files: ... static int GetEncoderClsid ...
    (microsoft.public.win32.programmer.gdi)
  • Re: OT: Why? Using eeePC as digital photo frame with server push...
    ... I suspect at least one JPEG codec still has a quirk when faced with unusually encoded images. ... The PaintShopPro encoder from v8 onwards is actually terminally broken in chroma subsampling but hardly anyone has noticed. ... same size and screen filling on the target screen, ... predictable formats, keeps aspect right. ...
    (sci.electronics.design)
  • Re: Jpeg Encoder: YCC Clipping error
    ... I'm a student and I have to write a Jpeg encoder using matlab. ... for me it looks all good but the generated JPEG files are ... subsampling, so the MCU ...
    (comp.compression)
  • Re: EncoderTransformation ignored, no errors produced.
    ... It will fail if the image that you loaded was not a jpeg image. ... flipped data before creating the CBitmap? ... memory (using the JPEG encoder), then vertically flip that image while ... JPEG compression and image transformation into two separate steps)? ...
    (microsoft.public.win32.programmer.gdi)