[Mr_Alert]

Seeing all the video converters being made (OK, it's just 2, but still!), I decided to dust up my old grayscale image converter from forever ago and improve it, colorize it, and make it do video. Here are the results:

• CLANNAD OP
  
• Some live action thing
  
• Sans logique

>>> Archive page for all three demos. <<<

This post has been edited by Lachesis: 13 April 2023 - 08:55 AM
Reason for edit: Replaced attachments with archive URLs.

[Dr Lancer-X]

Wonderful quality; I especially like how the text is crisp and clear. Still some cases of artifacting, but it looks very good.

EDIT: as expected, the live action looks great with this encoder.

[Wervyn]

I have to agree, this is really nice work, first encoder I've seen that actually does a passable job with video, instead of just "hey, that's kind of neat that you got that video into MZX". Being able to clearly read text on screen in a big part of it.

"I'm just a song from the 80's."

[mzxgiant]

Lancer's right -- I'm impressed, the text is the dead giveaway to how great this looks

[Lachesis]

I think your game has replaced Focus Point as the greatest MZX game of all time

[Sai'ke]

Oh ho ho, very FUNY :'(

[Pyro1588]

i forgot how much i liked clannad. i really should finish the after story. thank you for reminding me of this =)

[Exophase]

Impressive results. What's the algorithm?

[Sai'ke]

(It is impressive btw )

[CJA]

This converter is going to take a while to beat. I think the war is won for now.

However, what I'm unsure of at all is the feasibility of movies in MZX. Odds are that if you were going to go out of your way to make a movie, you'd probably want the movie to be something in itself. Uploading the 1 minute video to YouTube, standing alone, with no game, would probably get you a the same amount of viewing time than if you added it to a 30 minute MZX game and released it.

[Mr_Alert]

Looks like my fears of using dithering with the pixel-by-pixel character comparison function are unfounded. I've got improvements with all three videos by enabling dithering in the converter. Here is a look at the results of the converter over time. (3rd image was converted with the same version that converted the 3 videos in this thread)

The conversion algorithm is as follows:

• Convert image to grayscale
  
• Create 16-color grayscale palette from histogram
  
• Find minimum/maximum values of pixels in each tile and assign colors accordingly
  
• Create a character for each tile (assuming an SMZX mode 1-type color assignment from the 16-color palette)
  
• Reduce character set to 256 characters by finding the minimum distance of each character from every character before it (multiplying the distance by that tile's contrast between min/max to give higher-contrast areas more priority) and sorting by that minimum distance in descending order
  
• Map each tile to the reduced character set by comparing to each character and their reverse
  
• Find the average color of each palette entry using the original image and the pixels covered by each palette entry in the final result, scaling the colors to the grayscale brightness afterwards.

The only really new things compared to my old converter is the fact that it uses SMZX, the histogram-based palette stuff, the tile contrast weighting, and the colorization at the end (obviously inspired by Lancer's converter.) Since the colorization is pretty much just tacked on to the end of a grayscale converter, there's room for improvement in that area (that much is obvious from some parts of the videos.)

As for the feasibility of video in MegaZeux, I was actually more interested in using this converter to convert static images for another project I was working on.

[Dr Lancer-X]

Ah, so it's SMZX mode 1? I guess that explains why the colourisation step doesn't work quite so well.

[Mr_Alert]

No, it's SMZX mode 2, but it assigns grayscale values as though it were SMZX mode 1. Colorization would actually be a good deal worse if it were mode 1.

[smilymzx]

Only one comment on the 2nd movie:

You have been RickRoll'd.

Good movie quality, by the way!

This post has been edited by smilymzx: 18 January 2010 - 07:18 PM

[iamgreaser]

I'm sorry, but I don't particularly like it when I'm being rickrolled and the video desyncs.

Pretty flippin' sweet quality, though.

[Frobozz]

Very nice quality on the animes. Also when I saw "Some live action thing" I immediately realized what it was.

[Seventh Shade]

CJA, on Jan 17 2010, 08:27 PM, said:

However, what I'm unsure of at all is the feasibility of movies in MZX. Odds are that if you were going to go out of your way to make a movie, you'd probably want the movie to be something in itself. Uploading the 1 minute video to YouTube, standing alone, with no game, would probably get you a the same amount of viewing time than if you added it to a 30 minute MZX game and released it.

It might be okay for a very short title screen or intro video.

[Mr_Alert]

Well, it's been a while. I've made a few small improvements, like using histograms of the pixels covering the tiles using each color pair to make the mid-range grayscale levels instead of interpolating them mode 1-style. At this point, I can't think of much else that would improve this any further, so I'm just gonna go ahead and release the converter now. I'm only releasing the source code, but if anybody wants to compile win32 binaries or whatever, be my guest.

png2smzx converts a PNG image into an MZM file, a CHR file, and a PAL file (SMZX mode 2). It depends on libpng and uses the following syntax:

png2smzx in.png out.mzm out.chr out.pal

y4m2smzx converts a 640x350 YUV4MPEG stream into the raw palette, character set, and tile data used by the included player. It automatically skips or repeats frames to match the frame rate of the source stream to MZX speed 4, but this can be easily changed in the source code. It depends on mjpegtools and uses the following syntax:

y4m2smzx < in.yuv > out.raw

 smzxconv.tar.bz2 (15.31K)
Number of downloads: 65

[Frobozz]

I went to compile it, realized I lacked the libraries, and decided I was too lazy to do anything further. Oddly the makefile is failing for me in MinGW because it can't find cc. So I had to throw in a rule redefining cc as gcc.

This post has been edited by Frobozz: 29 January 2010 - 10:40 AM

[ajs]

Nice. Mind if I add png2smzx to utils/ in MZX?

--ajs.

[mzxgiant]

Sorry for the bump, I just felt this might be useful...

Compiled this for win32 (using MinGW32/MSYS)...

Attached File(s)

•  smzxconv_win32.zip (153.6K)
  Number of downloads: 40

[mzxgiant]

Something to note here after spending a few hours mucking with this...

Exporting a YUV from VLC (as I did) doesn't include a framerate in the header of the YUV file for some reason. Aaand without it, the program just silently quits. Later today (if Alert doesn't beat me to it) I'll probably re-compile my version with a fallback switch on the framerate and throw it up here for all that are interested.

[ajs]

I haven't tackled the mjpegtools dependency issue yet, but I've imported png2smzx into MZX proper:

http://github.com/aj...afde3481f642809

It will be shipped with the next version of MZX..

--ajs.

[Mr_Alert]

Patchings

New syntax for y4m2smzx is:

y4m2smzx [mzxspeed] [nnn:ddd] < in.y4m > out.raw

where nnn:ddd is the source frame rate in ratio form (24:1, 30000:1001, etc.)