N900 Camera JPEG compression
 

I found a way to adjust the JPEG compression quality on the N900's camera. I had a look round but could find any good info on this so my apologies if it's already been covered elsewhere.


Load up /etc/gdigicam/gdigicam-camerabin.conf in VI, leafpad etc

The default setting is to use 'dspjpegenc' to compress the raw images, however the quality setting has no effect, and seems to be stuck on 90.

By using the software compressor (jpegenc) and a quality setting of 100, my images are now coming out at around 3.5Mb compared to the original ~1Mb.

I've not had time to see if there is any real world difference in image quality, so post up your experiences.

I'd also love to know if anyone has found a way of increasing the video capture bitrate.

Here is my modified conf file - note you must change useconfigfile=true, and remove the comment marks under [imageenc]

A reboot is required to see changes...

/etc/gdigicam/gdigicam-camerabin.conf

[global]
# Set this to true to use the config from the file, and to false to
# use the values provided from the application.
useconfigfile=true

# Values specified are the values set by default by the application.
[videosrc]
element=v4l2camsrc

[imageenc]
element=jpegenc
quality=100

[videoenc]
element=dspmp4venc
#element=omx_mpeg4enc

[videomux]
element=hantromp4mux

[audiosrc]
element=pulsesrc

[audioenc]
element=nokiaaacenc
bitrate=128000
width=16
depth=16
rate=48000
channels=1

[imagepp]
#element=ipp

[vfsink]
element=xvimagesink
colorkey=16

Re: N900 Camera JPEG compression
 

can you post an image with software compression set to %100?

Re: N900 Camera JPEG compression
 

Nice find. I had played with the quality setting previously, but hadn't managed to make it do anything either. Your trick of using jpegenc is definitely a stroke of genius :)

Not sure if it's related, but when I first implemented the new config, the image viewer app was incredibly slow and needed to refresh every picture's thumbnail before it became usable again.. it's fine now though, so maybe that's no big deal.

I'll see if I can find some time and a stable setup tomorrow for shooting some IT8 targets to see if I can detect any tangible differences between this and default.. I suspect differences are going to be minimal at best in most cases, but hey -- if we can't have RAW, I'd still rather have my JPEGs as uncompressed as possible.

Re: N900 Camera JPEG compression
 

I dont mention any difference with new settings.

Believe it or not but here is a picture i took of some kind of bee while flying with the old camera settings on the n900.

http://www.sygysweb.nl/download/20100411_016.jpg

Everyone who still complains about the n900 camera is a n00b!

Re: N900 Camera JPEG compression
 

So far, I've not noticed any real world quality differences, but like others I'd prefer that compression isn't affecting the quality of my photos at all.

I've not had the slow thumbnail problem, but I did loose a photo yesterday and I'm pretty sure I didn't delete it - I'd had a couple of beers though so who knows!

Either way, I think a bit more testing needs to be done before people use this setting for their precious holiday snaps.


I'll post up some DSP vs software comparisons in a day or two.

Re: N900 Camera JPEG compression
 

Any updates on this thread?

Also I'm interested to know if there is a way of saving pictures in RAW format, even if we can't use it in real world due to large image size or time takes to save the image, we can use it as a basis for comparing image quality.

Re: N900 Camera JPEG compression
 

RAW should be doable but not through the camera UI... AFAIK there is a debug mode for the low level camera functions, but you would have to construct a front-end for it.

Re: N900 Camera JPEG compression
 

So, is it possible to Change the Photo to another file format like PNG or TIFF ? That would be real handy.

Re: N900 Camera JPEG compression
 

[imageenc]
element=jpegenc
quality=100

element is what needed to be altered to changed the format i think...

try something like: element=pngenc or element=tiffenc

but dont know if it'll work

Re: N900 Camera JPEG compression
 

Hey! Didn't know you were here :D
How do I even apply this btw? I've got no clue dude :S