Re: image quality of Labtec Webcam 2200
On Fri, 11 Sep 2009 09:09:20 +0200 Németh Márton nm...@freemail.hu wrote: 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#img9 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#img7 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? The error EAGAIN is normal when decoding pac7311 images, because they are rotated 90°. But this error should occur one time only. I looked at the raw image #1, and it seems that there are JPEG errors inside (sequences ff ff). There should be a problem in the pac7311 driver. Hans, may you confirm? -- Ken ar c'hentañ | ** Breizh ha Linux atav! ** Jef | http://moinejf.free.fr/ -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: image quality of Labtec Webcam 2200
Jean-Francois Moine wrote: On Fri, 11 Sep 2009 09:09:20 +0200 Németh Márton nm...@freemail.hu wrote: 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#img9 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#img7 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? The error EAGAIN is normal when decoding pac7311 images, because they are rotated 90°. But this error should occur one time only. I have the feeling that the Labtec Webcam 2200 is not based on the PAC7311 but on PAC7312. The PAC7312 also contains a microphone input and the Labtec Webcam 2200 also have a built-in microphone. See http://www.pixart.com.tw/productsditel.asp?ToPage=1productclassify_id=12productclassify2_id=33 for the datasheets. See also http://labtec.com/index.cfm/gear/details/EUR/EN,crid=30,contentid=761 . I looked at the raw image #1, and it seems that there are JPEG errors inside (sequences ff ff). There should be a problem in the pac7311 driver. Hans, may you confirm? -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: image quality of Labtec Webcam 2200
Actually it based on pac7302. Pac7311/02 also has support ( since gspca1 ). I checked some old logs of the pac, and the driver init for 7302 seems ok. The ff ff ff sequence, seems to been taken in account on conversion. (libv4lconvert) /* Special Pixart versions of the *_nbits functions, these remove the special ff ff ff xx sequences pixart cams insert from the bitstream */ #define pixart_fill_nbits(reservoir,nbits_in_reservoir,stream,nbits_wanted) \ This is really a tricky cam. I be back on windows to do further test. pd: Nemeth, i could reproduce your problems now. 2009/9/13 Németh Márton nm...@freemail.hu: Jean-Francois Moine wrote: On Fri, 11 Sep 2009 09:09:20 +0200 Németh Márton nm...@freemail.hu wrote: 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#img9 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#img7 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? The error EAGAIN is normal when decoding pac7311 images, because they are rotated 90°. But this error should occur one time only. I have the feeling that the Labtec Webcam 2200 is not based on the PAC7311 but on PAC7312. The PAC7312 also contains a microphone input and the Labtec Webcam 2200 also have a built-in microphone. See http://www.pixart.com.tw/productsditel.asp?ToPage=1productclassify_id=12productclassify2_id=33 for the datasheets. See also http://labtec.com/index.cfm/gear/details/EUR/EN,crid=30,contentid=761 . I looked at the raw image #1, and it seems that there are JPEG errors inside (sequences ff ff). There should be a problem in the pac7311 driver. Hans, may you confirm? -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: image quality of Labtec Webcam 2200
On 09/13/2009 04:42 PM, leandro Costantino wrote: Actually it based on pac7302. Pac7311/02 also has support ( since gspca1 ). I checked some old logs of the pac, and the driver init for 7302 seems ok. The ff ff ff sequence, seems to been taken in account on conversion. (libv4lconvert) /* Special Pixart versions of the *_nbits functions, these remove the special ff ff ff xx sequences pixart cams insert from the bitstream */ #define pixart_fill_nbits(reservoir,nbits_in_reservoir,stream,nbits_wanted) \ This is really a tricky cam. I be back on windows to do further test. Hey All I thought Hans will come in, in this discussion... Anyway, I introduced support for the PAC7311 in gspcaV1 in 2006 [1] Pixart is using a proprietary JEPG Format to code the image. It took me (and help from Jörg Schummer) more than a year to find out the basics to decode a frame. They have this 0xffxx markers in the stream, I don't know for what this is good, just skip it. And they have a MCU marker for each MCU. As we know so far, this MCU marker tells what Quantization table should be used for decoding the MCU. Hans did implement my findings into lib4vl and improved it :-) So, when you get this errors, this is due to a unknown format Pixart is using. I guess we should know what marker you get and how the image should look like. Don't forget, this is all re-engineered - guess work! Thomas [1] http://www.kaiser-linux.li/index.php?title=PAC7311 -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: image quality of Labtec Webcam 2200
Hi, On 09/13/2009 09:20 AM, Jean-Francois Moine wrote: On Fri, 11 Sep 2009 09:09:20 +0200 Németh Mártonnm...@freemail.hu wrote: 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#img9 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#img7 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? The error EAGAIN is normal when decoding pac7311 images, because they are rotated 90°. But this error should occur one time only. I looked at the raw image #1, and it seems that there are JPEG errors inside (sequences ff ff). There should be a problem in the pac7311 driver. Hans, may you confirm? The pac7311 / pac7302 are very cheap crap cams (I bought one brand new for 3 euros, and that was not in the bargain bin). These cams use a custom jpeg format, and we are very luky to be able to decompress this at all (thanks to some of the wizards who worked on the original gspca driver). Yes there are still some issues, but with no documentation what soever, and unreliable hardware (I've seen hang cams which needed to be unplugged / replugged to start working again), I'm afraid there is nothing we can do. Still if people want to work on improving support for them more power to then, I'll gladly help where I can. The ff ff you've found are special Pixart padding sequences, see tinyjpeg.c: pixart_fill_nbits() Also interesting is the comment about some of the special Pxiart markers in the tinyjpeg.c: pixart_decode_MCU_2x1_3planes() function. Which summaries what i've learned while getting pac7302 cams to work (to a certain extend). Regards, Hans -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: image quality of Labtec Webcam 2200
Hi, On 09/13/2009 05:59 PM, Thomas Kaiser wrote: I thought Hans will come in, in this discussion... Hey hey, its weekend, give me some time to respond already :) See my reply higher up in the thread. Regards, Hans -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: image quality of Labtec Webcam 2200
Nice, i will take a look.
Anyway, be aware, that the conversion error, is something expected
on pac7311, in fact, Hans have commented that on the libv4lconvert.
..
if (result) {
/* Pixart webcam's seem to regulary generate corrupt frames, which
are best thrown away to avoid flashes in the video stream. Tell
the upper layer this is an intermediate fault and it should try
again with a new buffer by setting errno to EAGAIN */
if (src_pix_fmt == V4L2_PIX_FMT_PJPG ||
data-flags V4LCONVERT_IS_SN9C20X) {
V4LCONVERT_ERR(decompressing JPEG: %s,
tinyjpeg_get_errorstring(data-jdec));
errno = EAGAIN;
return -1;
That's the result of the EAGAIN.
About, the half brightness picture, did that happens when autogain is off?
Best Regards
On Sat, Sep 12, 2009 at 2:16 AM, Németh Márton nm...@freemail.hu wrote:
Hello,
thank you for looking at this topic.
leandro Costantino wrote:
Hi ,
i tested it with 2.6.31-rc9 libvl 0.6.1 + svv and cannot reproduce.
301147.626826] gspca: probing 093a:2626
[301147.641578] gspca: probe ok
[301147.641607] gspca: probing 093a:2626
[301147.641770] gspca: probing 093a:2626
[301147.641829] usbcore: registered new interface driver pac7311
[301147.641835] pac7311: registered
I have the same dmesg output. My Labtec Webcam 2200 has the following labels
on the cable:
M/N: V-UCE52
P/N: 860-73
PID: CE73902
Maybe there is more than one revision of the Labtec Webcam 2200 and I have
one with a different hardware/firmware inside?
Could you try testing with svv.c app?
I used a bit modified svv.c to create the measurement result. The
modifications are to create the output HTML report and save the raw
and the BMP images. The display is not correct because I changed
the format from V4L2_PIX_FMT_RGB24 to V4L2_PIX_FMT_BGR24 to easily
save the result to BMP. The source code quality is not the best,
I am sorry about that, but I can still attach my source code which I
modified a little bit since my last report.
pd: quality is not the best, but works ok. Seem that the format is not
the proper or expected pjpeg on your streaming.
Do you think about USB transfer problem?
Regards,
Márton Németh
2009/9/11 Németh Márton nm...@freemail.hu:
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#img9
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#img7
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:
Re: image quality of Labtec Webcam 2200
leandro Costantino wrote:
Nice, i will take a look.
Anyway, be aware, that the conversion error, is something expected
on pac7311, in fact, Hans have commented that on the libv4lconvert.
..
if (result) {
/* Pixart webcam's seem to regulary generate corrupt frames, which
are best thrown away to avoid flashes in the video stream. Tell
the upper layer this is an intermediate fault and it should try
again with a new buffer by setting errno to EAGAIN */
if (src_pix_fmt == V4L2_PIX_FMT_PJPG ||
data-flags V4LCONVERT_IS_SN9C20X) {
V4LCONVERT_ERR(decompressing JPEG: %s,
tinyjpeg_get_errorstring(data-jdec));
errno = EAGAIN;
return -1;
That's the result of the EAGAIN.
The corrupted data coming from the device would be one reason. An other reason
could be the limitation of the libv4l 0.6.1 that it cannot understand the raw
data
coming from the webcam. Maybe the raw data does not fulfill the JPEG
specification
but still could have some meaning -- which we don't understand at the moment.
The
different types of error messages mean for me that at least some of them could
be
solved (i.e. unknown huffman code).
About, the half brightness picture, did that happens when autogain is off?
Yes, I tried to switch the Auto Gain control off before starting a
measurement.
The half brightness pictures appears time to time.
Regards,
Márton Németh
Best Regards
On Sat, Sep 12, 2009 at 2:16 AM, Németh Márton nm...@freemail.hu wrote:
Hello,
thank you for looking at this topic.
leandro Costantino wrote:
Hi ,
i tested it with 2.6.31-rc9 libvl 0.6.1 + svv and cannot reproduce.
301147.626826] gspca: probing 093a:2626
[301147.641578] gspca: probe ok
[301147.641607] gspca: probing 093a:2626
[301147.641770] gspca: probing 093a:2626
[301147.641829] usbcore: registered new interface driver pac7311
[301147.641835] pac7311: registered
I have the same dmesg output. My Labtec Webcam 2200 has the following labels
on the cable:
M/N: V-UCE52
P/N: 860-73
PID: CE73902
Maybe there is more than one revision of the Labtec Webcam 2200 and I have
one with a different hardware/firmware inside?
Could you try testing with svv.c app?
I used a bit modified svv.c to create the measurement result. The
modifications are to create the output HTML report and save the raw
and the BMP images. The display is not correct because I changed
the format from V4L2_PIX_FMT_RGB24 to V4L2_PIX_FMT_BGR24 to easily
save the result to BMP. The source code quality is not the best,
I am sorry about that, but I can still attach my source code which I
modified a little bit since my last report.
pd: quality is not the best, but works ok. Seem that the format is not
the proper or expected pjpeg on your streaming.
Do you think about USB transfer problem?
Regards,
Márton Németh
2009/9/11 Németh Márton nm...@freemail.hu:
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#img9
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#img7
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
Re: image quality of Labtec Webcam 2200
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#img9 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#img7 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
Re: image quality of Labtec Webcam 2200
Hi , i tested it with 2.6.31-rc9 libvl 0.6.1 + svv and cannot reproduce. 301147.626826] gspca: probing 093a:2626 [301147.641578] gspca: probe ok [301147.641607] gspca: probing 093a:2626 [301147.641770] gspca: probing 093a:2626 [301147.641829] usbcore: registered new interface driver pac7311 [301147.641835] pac7311: registered Could you try testing with svv.c app? pd: quality is not the best, but works ok. Seem that the format is not the proper or expected pjpeg on your streaming. 2009/9/11 Németh Márton nm...@freemail.hu: 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#img9 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#img7 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
Re: image quality of Labtec Webcam 2200
Also , about the negative value. It happens to when using Pac7311 on libv4l_convert. Usually it an -EAGAIN, that should be ignored. svv application, just ignore that, and another apps take in account. But would be nice to re test your webcam to find where the real problem is. Best Regards 2009/9/11 Németh Márton nm...@freemail.hu: 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#img9 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#img7 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:
