William F Pokorny <ano### [at] anonymousorg> wrote:
>
> but I fully admit I'm just poking the matrix with a stick to
> see what happens. To some extent, I wonder about why it does what it
> does, but I care more about whether what it does might be useful.
>

That is also my usual method of playing with matrices, ha-- because I still have
a hard time understanding how they work and how to use them. I like your video
though; I need to experiment with your code example to see how I can break it!

------------
[In Windows 10]  I thought I should mention something: In the newsgroups'
standard web portal that I use, the Firefox 'previews' of your .mp4 videos do
not play -- with the message "Video cannot be played because the file is
corrupt." (which is not the case!) As a comparison: Josh's .mp4 animation in his
recent post  "Go home, RSOCP, yer drunk" plays fine in the Firefox preview.

So I downloaded your video-- and it plays fine in *most* of my Windows 10 media
players: VLC Media Player, SM Player, and even my old VirtualDub2. But it does
not play in Windows' own Media Player (a black screen)-- and actually breaks
Irfanview (the app hangs and has to be terminated via Windows Task Manager.)
Irfanview will usually play just about any video that I throw at it, so its
behavior in this case is very weird.

In VLC Media Player, I took a look at your first posted video's encoding
statistics:

Codec: H264-MPEG-4 AVC (part 10) (avc1)
Video Resolution: 450 X 450
Buffer Dimensions: 464 X 482
Decoded Format: Planar 4:4:4 YUV
Color Primaries: ITU-R BT.709

I did some research (yet again!) about video encoding and codecs, because it is
all so complicated to remember. Your video's stats are fairly standard stuff
AFAIU-- except for the 4:4:4 chroma subsampling.  4:2:0 is the typical scheme
for h.264; I use that myself. Take a look at Wikipedia's "h.264" page,
particularly the subsection "Feature support in particular profiles". It appears
that 4:4:4 is only supported in a particular high-end 'flavor' of h.264; perhaps
that presents a problem for Firefox, and/or for Windows 10's built-in video
codecs.

Or maybe you encoded the videos using 10-bit colors rather than the more
standard 8-bit?

I also did a search for possible Firefox problems regarding playback of
h.264 .mp4 files, but found nothing that would be helpful-- except for this
possibility:

"Yes, Firefox can play 4:4:4 videos, but only if your hardware and system
settings support it; this is because the capability to play 4:4:4 video depends
on your graphics card and the video codec used, not solely on the browser
itself."

(By the way: I had the same video-playback problems with your December 2024
post,
 "New f_dnoise(), modified f_dturbulence(). yuqk R17"
but forgot to mention it at the time.)

Post a reply to this message