So you use your own MRLE encoder instead of Microsoft's codec? How does it
work? I use only codecs installed in Windows. Including the AVI file
container - I use AVI support in Windows.
AFAIK lossless audio codecs aren't technically possible in ACM. It means
FLAC isn't an option for me, because I need ACM codec, and ACM requires the
constant bitrate. (ACM is part of Windows API for audio compression.)
IMO the best option for audio would be to save the SAA register values. I
mean the best i.e. the smallest file size. That would make very short files,
but nobody would replay those files outside our custom player.
A.
-----Původní zpráva-----
From: Simon Owen
Sent: Friday, March 30, 2012 10:52 PM
To: [email protected]
Subject: Re: ASCD 0.98 WIP 2 released
On 30/03/2012 21:15, Aleš Keprt wrote:
I think the audio track needs to be compressed to MP3 in an external
program.
MP3 would have been good, though I don't know if finding a legal free
codec for the encoding might be a problem? The demo AVI I posted a few
years ago was run through VirtualDub to convert the audio to MP3, so it
was a reasonable size for my website.
My original plan was to record to a lossless file, and let the user
transcode to their preferred video+audio format. In practice, I can't
imagine many people will bother with that, so cutting the original video
size is better. Finding the right balance between size and quality is
the tricky part.
Another issue I had was sticking to simple formats for speed, and so I
could implement them directly in SimCoupe, to reduce dependencies on
different platforms. Decent audio encoders certainly weren't trivial!
MRLE is an big unknown to me. Unfortunately VirtualDub cannot write MRLE
files so I did't do any tests with it.
I think Microsoft dropped the MRLE encoder in newer versions of Windows,
maybe after XP. I think VirtualDub is completely dependent on local
codecs for output too. You could probably use ffmpeg to output MRLE
under Windows, if you wanted to compare.
A friend sent me his test video in MRLE he recorded in another ZXS
emulator and it is quite small, but it is really
new thing for me.
I remembered finding that RealSpectrum videos were small, and I found it
was using MRLE for lossless video. I researched that and found it was
surprisingly simple.
When we compared MRLE to SCLS, the MRLE file was 6x bigger.
I hadn't heard of SCLS before, but it does sound like it works better
than MRLE. Perhaps some of the size difference is that I force
keyframes every second, to improve seeking resolution?
Audio still takes up the bulk of the video size, so there's probably
more to be gained on that side. FLAC would have been nice :)
Si
-----------------------------------------
Mgr. Aleš Keprt, Ph.D.
private: [email protected], www.keprt.cz
office: Moravian College / Moravská vysoká škola Olomouc, [email protected]
