Márton Németh wrote:
> Hi,
>
> I have a Labtec Webcam 2200 and I have problems with the image quality
> with Linux 2.6.31 + libv4l 0.6.1. I made some experiments and stored
> each captured image as raw data and when libv4l was able to convert
> then I also stored the result as bmp.
>
> You can find my results at
> http://v4l-test.sourceforge.net/results/test-20090911/index.html
> There are three types of problems:
> a) Sometimes the picture contains a 8x8 pixel error, like in image #9
> http://v4l-test.sourceforge.net/results/test-20090911/index.html#img00009
> b) Sometimes the brightness of the half picture is changed, like in
> images #7, #36 and #37
> http://v4l-test.sourceforge.net/results/test-20090911/index.html#img00007
> http://v4l-test.sourceforge.net/results/test-20090911/index.html#img00036
> http://v4l-test.sourceforge.net/results/test-20090911/index.html#img00037
> c) Sometimes the libv4l cannot convert the raw image and the errno
> is set to EAGAIN (11), for example image #1, #2 and #3
>
> Do you know how can I fix these problems?
I investigated the c) point a little bit. When I get a negative return value
from the v4lconvert_convert() function then I print out the error message what
the
v4lconvert_get_error_message() function returns. With the result log file
I executed a "grep v4l-convert |sort |uniq" command. All the error messages are
coming from the tinyjpeg.c (Small jpeg decoder library):
v4l-convert: error decompressing JPEG: error: more then 63 AC components (65)
in huffman unit
v4l-convert: error decompressing JPEG: error: more then 63 AC components (66)
in huffman unit
v4l-convert: error decompressing JPEG: error: more then 63 AC components (67)
in huffman unit
v4l-convert: error decompressing JPEG: error: more then 63 AC components (68)
in huffman unit
v4l-convert: error decompressing JPEG: error: more then 63 AC components (69)
in huffman unit
v4l-convert: error decompressing JPEG: error: more then 63 AC components (70)
in huffman unit
v4l-convert: error decompressing JPEG: error: more then 63 AC components (71)
in huffman unit
v4l-convert: error decompressing JPEG: error: more then 63 AC components (72)
in huffman unit
v4l-convert: error decompressing JPEG: error: more then 63 AC components (73)
in huffman unit
v4l-convert: error decompressing JPEG: error: more then 63 AC components (75)
in huffman unit
v4l-convert: error decompressing JPEG: error: more then 63 AC components (76)
in huffman unit
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x00
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x01
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x02
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x04
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x08
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x09
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x0a
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x10
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x12
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x14
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x1a
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x1b
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x1c
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x1f
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x80
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x82
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x87
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x88
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x89
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x8a
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x8b
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x8c
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x8d
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x8e
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x8f
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x90
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x91
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x92
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x93
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x94
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x95
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x96
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x97
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x99
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x9b
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x9c
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x9d
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x9e
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0x9f
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xa3
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xa5
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xa6
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xa7
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xa9
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xaa
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xab
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xad
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xaf
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xb3
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xb5
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xb7
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xb8
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xb9
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xbc
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xbd
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xbe
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xbf
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xc0
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xc4
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xc6
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xc7
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xc9
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xcb
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xcc
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xcf
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xd1
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xd2
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xd3
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xd4
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xdc
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xdf
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xe5
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xe7
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xe8
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xea
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xeb
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xec
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xf0
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xf2
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xf4
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xf5
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xf8
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xf9
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xfa
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xfc
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xfe
v4l-convert: error decompressing JPEG: Pixart JPEG error: invalid MCU marker:
0xff
v4l-convert: error decompressing JPEG: Pixart JPEG error, stream does not end
with EOF marker
v4l-convert: error decompressing JPEG: unknown huffman code: 0000ff81
v4l-convert: error decompressing JPEG: unknown huffman code: 0000ffec
v4l-convert: error decompressing JPEG: unknown huffman code: 0000ffff
Regards,
Márton Németh
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