Development reached stage
when we can make overview of video modes available:
But first little refreshing of memories :
Hi-color here means more than 16 colors at once on screen.
Based on fast palette change during video displaying, with special,
synhronised code. First SW using it was Spectrum 512. In meantime
some newer SW is developed, on same base, but with more options, better
quality, and SW for PC - what is important when we need to convert
thousands of pictures for animations.
Hi-color can have 4096 colors at once on STE, or even about 30K
perceptual, if alternating 2 little different palettes between fields
(2 fields make 1 frame by TV) . But 4096 colors per screen means
not that any pixel may have any of 4096 colors - we have maximum of
colors per horizontal line - what is less than line pixel count,
because palette change speed is limited. Color/line count goes usually
from 48 to 80 (later only with CATA) . It is usually enough for pretty
Interesting is to compare it with 256 color, indexed mode - what may
see on Falcon or TT (+VGA, etc) :
256 color, indexed mode means that any pixel can have any of 256
colors, defined in palette, what holds 256 different color nuances,
usually defined with 18 bits - so from 256K colors (like 512 by
ST). In most of cases, 256 colors will look better than 4096. Why
? Because there is more nuance selectable in palette, and no special
line color count limit. RAM usage of 2 ways is pretty similar.
And STE hi-color occupies CPU heavily during line displaying - CPU is
free for other things only in top and bottom border periods.
After this rhetoric, let's see available modes developed by me, and
supported by Photochrome and HigheSTcolor converters - still developed
by Douglas Little and Cyg :
First param. is resolution Hor x Vert pixels, then frames per
second, palettes - SP or DP (single or dual) and colors per line.
Data rate is with audio (what is only 25KB/sec in all cases)
Mode 1: 320x158px, 12.5 fps, 48c/l. SP. Data
rate: 519 KB/sec.
Only this and mode 9 work on UltraSatan - if SD card is
Following modes are all for CATA, fast read:
Mode 2: 320x159px, 25 fps, 48c/l - standard PCS timing. SP.
Data rate : 1013 KB/sec.
Good compatibility with possible timing variations.
Mode 3: 320x199px, 25 fps, 48c/l - standard PCS timing. SP.
Data rate : 1427 KB/sec.
Good compatibility with possible timing variations.
Obsolete - will be not supported in standard CATA ROM.
Mode 4: 320x198px, 25 fps, 80c/l . SP or DP. Data rate:
SP: 1625 KB/sec . DP: 2450 KB/sec.
Indeed best quality.
Mode 5: 416x228px Overscan, 25 fps, 48c/l. DP (can SP
too, but not recommended - gives not lower datarate).
Data rate: 2375 KB/sec.
More res=more details. Ideal for less colorful stuff.
Mode 6: 320x199px. 25 fps, 54c/l. SP or DP. Data rate
SP: 1425 KB/sec. DP: 2050 KB/sec .
Uses Cyg's 54c/l . Good for animated/cartoon.
Mode 7: 320x198px. 50 fps. 48c/l. SP (of course) . Data
rate: 2500 KB/sec .
STE display is actually 50fps, progressive - so why not playing
in it's native mode, if disk transfer is fast enough. And era of HFR is
coming (High Frame Rate - Hobbit, Avatar 2) . It is easy to
convert usual TV, 25 fps interlaced to 50 fps progressive, lower
vertical res - exactly good for our prehistoric STE !
Mode 8: 320x240px, 25 fps, 48c/l. DP . Data
rate: 2088 KB/sec .
Good for old-fashion 4:3 AR material.
Mode 9: 320x78px,
25 fps, 48c/l. SP. Scanline grille - see screenshots lower. Data
rate: 517 KB/sec.
Only this and mode 1 work on UltraSatan - if SD card is
fast. For now, audio is always mono, 25033 Hz, and 8-bit (that
can not be other).
May go on stereo, 25033 Hz in some cases - will see it later.
After couple months spent with this, I must say that results are better
than I ever thought. Proper error diffusion and 30K colors make it
really good. And even 50 fps is possible with hi-color. From now,
I focus on finalising and polishing SW, publishung CATA design and ROM
code. And: new internal IDE adapter for STE, ST machines, where same
speed can be achieved - so same AV modes. For people may be
interested: CATA is designed with speed
as main concern. It is not much compatible - max. potential can reach
only on STE, with simple HW mod in machine. It can not work together
with any other cartridge port adapter - only if attached alone. You
need some newer, faster Compact Flash card for AV playback.
Because it works on port not designed for hard disks, it boots not in
usual way - like ACSI hard disks (SCSI via ACSI/SCSI adapter,
Satandisks). Driver installs via cartridge auto-run code of TOS. It
executes before regular hard disk booting. In any case, CATA can work
together with some ACSI attached disk - only need to take care about
max. 14 logical drives limit.
Driver SW: it is my 'regular' TOS/DOS compatible driver, with
selectable boot partition etc. You can attach CF card
simply to PC, MAC and transfer files via Total Commander or other file
Some may ask: why this was not made around 1990,
when Atari STE arrived on market ? As I know, AV playback on any home,
PC computer was not possible in those years. Here mean some
quality playback (so 25fps, decent resolution) , of recorded content
(by camera, from TV, or like). Even if now I managed it on 8Mhz STE, in
1990 some requirements missed. In first place: hard disks were
too slow for this, and capacity was low. Digital video processing was
in very early stage, and people had no access to content, processing
SW. And no quality video grabbers were available. For instance, around
1996 I bought not cheap Asus graph. card with grabbing (capturing)
capability. It was limited on some 10 fps at 320x240, and colors were
not much accurate.
Of course, this is just demonstration of what is possible
with good SW on prehistoric HW aided with modern storage. Watching
movies with 16 or 4096 colors
and low resolution
is not exactly what we want in 21st century. And compression is not an
option - 8MHz CPU is simply not capable for decoding video of some
resolution at decent framerate.
But we can achieve smooth motion of 25 frames/sec (PAL) with prepared
frames, and just reading them in sequence into video RAM from hard disk
with basic sync. and audio. It has price: need very fast hard disk
(card) + adapter, and plenty of disk space.
Hi-color AV playback on STE,
equipped with UltraSatan:
25 fps, using old technique "scanline grille" :
Because limited disk speed, showing only every
second line - this allows 25 fps with UltraSatan !
And what is better example for this if not Tomb Raider clips - where I
saw it first. Original is 320x120px, 15fps. Converted to 320x80,
25fps, without speed change. DL player and 2 clips 62 MB .
Another PC game intro, converted from 15 to 25 fps, resolution is same
as org. BZintro 14MB avi .
Here is preliminary version of playback SW for
interesting demo video, from 1987: USdemo 29MB. Thanks to
Atarimania for hosting this old video.
copying files on your SD card, you need to defragment target partition.
It must be one of first 2 partitions if you have 512MB large ones (AV
file must be in first 1GB). For now, only ACSI target 0 is supported
(default one). If you copied files on target partition in order, and
did not delete, then it must be defragmented. Otherwise run some
defrag. SW. It may take some time, but is useful overall. In case of
TOS/DOS partition you may defrag on PC too. But Windows XP defragmenter
is not really good for this - it will not defragment free space. Then
whatever you copy on, will become fragmented. So, run Windows XP
defragmenter after you copied large AV file on SD card.
You need fast SD card for this - min transfer rate is 1100
KB/sec. Please run speed test in case of not knowing speed,
and/or if playback is bad. Speed t.
You may try in emulators Steem or Hatari (the real thing
is STE, of course) - then must use ACSI hard disk emulation (Hatari),
Pasti in Steem, and using image file of hard disk. If this confuses
you, search little around - was explained, discussed many times. May
try with ST too - then will be no sound, and may look ugly at some
places (less colors). Tested with PP, AHDI, ICD, Hddriver .
Updated player 3KB . Plays from
any ACSI target, any location on Flash card, no 1GB limit, BigDOS
Expected question: I want to convert myself some video for
STE . How to do it ? Link to page with detailed description is
right above. For beginning some hints: you need SW capable of
audio and image sequence from usual sources like AVI, DVD, Mpeg, Mov,
FLV etc. Virtual Dub is certainly one of the bests for that - and has
lot of external filters avaialable - freeware. Then need SW for audio
manipulation - like Audacity. Need SW for converting standard
format images (PNG, BMP) to Atari STE hi-color format -
Photochrome and/or Cyg hi-color converter. Both are currently
under improvement. Some special SW for muxing images and audio to AV
file - will be posted here. When you have completed AV file, just need
to copy on your SD card and run playback SW. Currently, I update
Drive Image too, so can handle larger flash cards. Stay tuned
Technical background for interested
So looks map of fragmented partition in CHKDSK3 . With it you can
defragment - called "Compress Disk" in CHKDSK3. By larger partitions it
may take some time ..
Hint for fast defragment of SD card: attach to PC with card
reader. If it is TOS/DOS compatible, you may use Total Commander for
instance. Then move all files, directories from partititon to some DIR
on PC. After it, just copy files back to SD card. They will be
playback with CATA:
I currently work on
high-color movie playback for Atari STE - where can play AV of any
length, even with only 512KB in machine. Only limit is storage
capacity - and speed. By using Photochrome PCS
images and displaying code. It allows up to 4096 colors on 1 screen. Or
even 30000 (perceptual) if we alternate colors slightly for 1 frame
shows 2x at 25fps and 50Hz display rate).
Significant quality improvement is achieved in last month - thanks to
Douglas Little's updates of Photochrome, doing better
preprocessing of images + making 80 colors/line mode with CATA (thanks
to Cyg for idea)..
I think that at moment (Nov. 20 2012) we reached aprox. maximum what is
possible with STE machine. It stays for 320x200 resolution, 25 fps with
30K colors, using cartridge port IDE adapter and small mod in STE (to
get enough load speed). Data rate is extremely high: 2.5 MB/sec.
You need some faster CF card for it - my 4GB Kingston can not ensure
stable work with it - there is many error during playback. Sandisk
Ultra (30MB/sec) is OK .
The key for good looking video on STE: proper preprocessing of
video. To have nice gradients (like sky, human face and similar) we
need to use dithering (called error diffusion too) during color
Photochrome current dev. version does error diffusion pretty good. But
there are still some smaller errors sometimes. I looked for longer time
SW capable for quality dithering/ED . For single palette (4096 c.) is
best to use Photoshop and XiQuantizer plugin, Sierra 24a error
diffusion during color reduction - because it produces stable pattern
on static parts. Similar would be good by reduction to 30K colors
(15bpp), but don't see SW capable. Instead , I used ImageMagick
ordered-dither o8x8,32 (32 means color/channel, with 3 base
colors it makes 32 pow 3 = 30K colors). Even better is to use Virtual
Dub filter 'Error diffusion' - can set bit depth for each channel, etc.
More about preprocessing and what SW to use - soon.
416x228px, 30K perceptual colors. But only 48
colors/line - no time for more. Still, looks pretty good, and bigger
res. makes details better:
Overscan 7.5MB. this
really pushes STE to limits. Used overscan 416x228px, mostly based on
Alien's article about overscan on ST(E), then last beta of Photochrome
with support for custom width, superfast loading from cartridge port,
where part of bitmap is loaded interleaved with color data, ahead -
only way to achieve loading of some 50KB/frame, only for bitmap, + 50K
Test 700 KB. 6 sec clip.
Src. from 1995. May be familiar for PC users from that period. It was
actually first really good video I saw on PC.
Comparing playback on PC and STE: Needed PC with min 4MB
RAM, faster 486, but recommended was Pentium (100MHz) and 8MB RAM.
Mpeg1 packed demo of 5-6 sec is 700KB.
STE: 8MHz, 512KB RAM enough. Need special hard disk adapter and
small mod. File size is 15MB - price you must pay when no CPU power for
Reminder: Mpeg1 was used by VCD - first commercial media/format
for digital AV. Quality was little better than VHS, on 1CD could put
max some 80 min. It was never much popular - couple years later
I don't give demos now, runnable on emulators, because:
mode with alternating color data will not look well on usual monitors
(which can not work at 50Hz). Files would be pretty long. Steem and
Hatari show overscan, but not flawless - Steem cuts off 16-16px left
and right, Hatari has error at right side. Not to mention additional
time needed for doing them.
Following examples are all made with 80 colors/line, 320x200px, dual
palette and mostly 'ordered-dither o8x8,32'
preprocessing. I can not give demos usable on emulators - 80
colors/line mode works not on them.
So, STE video/audios captured.
Promo Promotional video of popular
Atari ST game. Src. looks nothing better. 2m 47s. 20MB.
Older txt. and conversions:
However, it is very demanding considering data rate needed for
fullscreen, 25 fps playback - about 1250 KB/sec is needed. Worse:
hi-color displaying occupies CPU 100% during scanlines, so we have only
about 35% (max) CPU time available for loading from disk. DMA transfers
? Not possible - DMA will destroy accurate timing of hi-color
displaying. So, 1250 KB/sec in 1/3 time ? Far from possible with usual
disk transfer speeds. Not to mention that FAT16 filesystem adds
additional slowdowns. Still, it is possible, but only with little
reduced screen size and CATA IDE adapter + small mod in STE. With
line count to 160, what is btw, good for 16:9 AR sources, we will have
more CPU time avail. (48%) and less data rate (1050KB/sec). With that
datarate, about 1 hour of AV will fit on average 4GB CF card
(3700MB). I will not
write here more details for now, because CATA is not yet available.
Made some demos, how it looks, and you can try them with Steem or
Hatari. Hard caseAnimFlying
DL AVI (8MB) This is
320x176 px. Absolute maximum with CATA and reading in black periods..
About 40% of time is available
for loading, and 1125 KB/sec is needed. Possible only with very fast
hard disk IF + fast disk or CF card - later is better.
Measured with CATA on STE with mod on R/W line, 4GB Kingston CF
Fullscreen playback: DL AVI (6.5MB) Funny scene
:-) 3 min cartoon (22MB AVI)
This is made by loading color data during scanlines, what
requires accurate CPU timing + using little irregular disk access -
because I can not use Read Multiple. Tested with 4GB Sandisk and
Kingston cards, newer ones, which are pretty fast. On older ones will
for sure not work. Disk space for this resolution is
80MB/min. About pic. quality: don't expect miracles.
are very limited - 4096 colors is just not enough. As I see, day scenes
in nature usually look very good. Dark scenes will never be good, right
because low color count . Can make to look little better with more
dithering, but it may be not good for some other scenes. Basically,
best is to convert every scene with best settings for it. Cartoons
usually look very good.
We talk here about 4096 colors, but it is simplification - so
much colors can be only on whole screen. Used techniques, which update
palette during scanlines can achieve around 50 colors max per 1 hor.
line. It may be serious problem by gradients for instance.
54 colors/line (MPP) with 48 colors/line +
Even with less colors/line, error diffusion makes it much better. Human
eye is more sensitive for color differences in small areas, than on
accurate colors self.
After couple years from first videos and playing SW I did some
major changes, improvements: changed structure of interleaved LAV
(limited audio/video) files. With old format playback was not smooth
from hard disk partitions bigger than 128MB, because of AHDI large
sectors. New format will play well even from 1GB partitions with sector
sizes of 16KB (Falcon). Made new player SW, what works with less CPU
load, dropped not really necessary seeking options - there is only
abort key. And it works well on Falcon now.
All files are with audio, but audio works only on STE &
Falcon (TT ?) machines.
Keys during playback: Right Shift - abort play & select other LAV or exit Left
To have smooth playback without slowdowns, audio repeating and
desync fast hard disk/Flash
card and adapter are necessary. Playback program has speed
(transfer rate) measuring. Select some file with size of min. 5MB
(best some LAV file, of course) for test. It will display after few
secs transfer rate in KB/sec. About 1000 KB/sec is usually good enough.
So, no Satandisk, but UltraSatan may be OK, however speed depends from
used SD card too. IDE should be about 1200 KB/sec with any decent
driver and CF card or drive. Of course when no byte-swap (then may
using twisted cable and special driver). 5785 KB/sec is speed in
with emulated ACSI hard disk, just to mention (on real ST not
possible). Other requirement is 50 Hz video refresh rate, so PAL only.
Falcon not with VGA, but RGB monitor or TV, set to PAL mode.