valadaptive
Almost no file size decrease by png compression level
Hello,
comparing
source image original file size = 89298
ntsc-rs-cli --input image_source/nanda_PAL.jpg --output NANDA-0.png -p nanda_initial.json --single-frame-time 1 -c png --compression-level 0
with
ntsc-rs-cli --input image_source/nanda_PAL.jpg --output NANDA-9.png -p nanda_initial.json --single-frame-time 1 -c png --compression-level 9
results in a file size ratio of
> 3989646/3340887
[1] 1.194188
of compression 0 vs. 9 which is not that much. Saving a frame from GUI results in a much smaller file size.
Good point, my mistake, there is no difference to the GUI, but using some external png converter (xnview) with compression 9 (input png, output png) it results in 599397 using the output of ntsc-rs as input - which is
> 3989646/599397
[1] 6.656099
So the switch in the GUI button save frame does not result in the possible file size reduction while creating png compared to what's probably possible.
btw - png compression is lossless?
I'm trying this on my own machine, and the output size for a sample frame is ~800KB. Compressing it with oxipng -o max gives 500KB. How are you getting 4MB files? What's your output resolution?
Is it possible that the encoder is somehow outputting 16-bit PNGs instead of 8-bit ones? This shouldn't be happening, but there might be some more Debian-specific codec weirdness.
btw - png compression is lossless?
Yes
this was create by the 0.9.2 standalone gui version:
$ mediainfo nanda_initial_orig.png
General
Complete name : nanda_initial_orig.png
Format : PNG
Format/Info : Portable Network Graphic
File size : 2.23 MiB
Image
Format : PNG
Format/Info : Portable Network Graphic
Compression : Deflate
Width : 640 pixels
Height : 480 pixels
Color space : RGB
Bit depth : 8 bits
Compression mode : Lossless
Stream size : 2.23 MiB (100%)
the input was
$ mediainfo image_source/nanda_PAL.jpg
General
Complete name : image_source/nanda_PAL.jpg
Format : JPEG
File size : 87.2 KiB
Image
Format : JPEG
Width : 768 pixels
Height : 576 pixels
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Compression mode : Lossy
Stream size : 87.2 KiB (100%)
...just repeated it with the GUI, same result.
Can you upload the original image and settings preset so I can try to replicate this? (EDIT: hang on, now it's 2 MB and not 4?)
sure
https://raw.githubusercontent.com/abcnorio/aas-mult/refs/heads/main/image_source/nanda_PAL.jpg
and profile
https://raw.githubusercontent.com/abcnorio/aas-mult/refs/heads/main/nanda_initial.json
the cli version created calls (see start of this thread for copy&paste) resulted indeed in
-rw-r--r-- 1 xxx xxx 3989646 9. Apr 10:18 NANDA-0.png
-rw-r--r-- 1 xxx xxx 3340887 9. Apr 10:19 NANDA-9.png
compared to GUI
2336198
but this diff seems to be due to resolution - the cli version does not change the resolution (?) which is nothing to complain about. The diff correlates with resolution.
$ mediainfo NANDA-0.png
General
Complete name : NANDA-0.png
Format : PNG
Format/Info : Portable Network Graphic
File size : 3.80 MiB
Image
Format : PNG
Format/Info : Portable Network Graphic
Compression : Deflate
Width : 768 pixels
Height : 576 pixels
Color space : RGB
Bit depth : 8 bits
Compression mode : Lossless
Stream size : 3.80 MiB (100%)
This explains the file size diff between GUI (save frame) and cli output but not the overall png compression.
So just to confirm, this is the frame at t = 1, as rendered by ntsc-rs-cli -- --input /tmp/nanda_PAL.jpg --output /tmp/NANDA-0.png -p /tmp/nanda_initial.json --single-frame-time 1 -c png --compression-level 9:
For me, it's 1.05 MB:
$ mediainfo NANDA-0.png
General
Complete name : NANDA-0.png
Format : PNG
Format/Info : Portable Network Graphic
File size : 1.05 MiB
Image
Format : PNG
Format/Info : Portable Network Graphic
Compression : Deflate
Format settings : Linear
Width : 768 pixels
Height : 576 pixels
Display aspect ratio : 4:3
Color space : RGB
Bit depth : 8 bits
Compression mode : Lossless
Stream size : 1.05 MiB (100%)
Not sure what's going on here. Maybe I just need to bundle my own GStreamer libraries to avoid weird platform-specific codec differences?
Sounds like a gstreamer problem, because image, json, bash call, ntsc-rs-cli version, etc. are identical. Maybe it makes sense to do some static linking and provide a bundle. When there is time will try that on fedora on a different computer next few days.
Another thing is that this was done on a deb-multimedia-org gstreamer deb package env because there was no chance yet to properly downgrade from that repo. Trying to remove packages resulted in a huge amount of files to be uninstalled... still thinking how to do that in an elegant way without much effort to reinstall stuff. I will try on a different Debian without any foreign repos and sent a report here. Maybe native Debian will just work out. Ok?
Short update - using plain debian gstreamer libs (1.22.0-2+deb12uX) whereas X number differs in accordance to the lib itself, and the same jpg and profile it results in 2.20 MB -> the deb-multimedia.org gstreamer lib resulted in 2.23 MB (both with 640x480 resolution). Thus, there is no real difference.