OK, I can let the user choose audio codec. I think the audio track needs to
be compressed to MP3 in an external program. I didn't want to spend a lot of
time with my avi writer and I don't have any experience with writing mp3, so
I used ADPCM. So the question is if ADPCM converted to MP3 has more noise
than PCM converted to MP3. Or AAC.
MRLE is an big unknown to me. Unfortunately VirtualDub cannot write MRLE
files so I did't do any tests with it. (At least my VDub - it can read MRLE,
but cannot write it.) 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 never tested MRLE. When we compared MRLE to SCLS, the MRLE file was 6x
bigger. But that is just a single test, so it's not representative. Since
MRLE codec is present in each Windows (and MPlayer supports it as well) I
think you your approach is good.
Aley
-----Původní zpráva-----
From: Simon Owen
Sent: Friday, March 30, 2012 9:44 PM
To: [email protected]
Subject: Re: ASCD 0.98 WIP 2 released
On 28/03/2012 19:27, Aleš Keprt wrote:
My final choice is Microsoft ADPCM, its bitrate is 384 kbps (for 48kHz
stereo), i.e. 172 MB per hour, and I think the audio quality is good.
I tried ADPCM for SimCoupe but wasn't very happy with it. MS-ADPCM was
brighter than IMA-ADPCM, but still seemed to have too much extra noise
and swooshiness (for want of a better word!).
It will depend on what you're recording too. Spot effect and pure notes
are probably fine, but it struggled with rapid note changes in some
music. My early recordings were of Manic Miner, and it was the in-game
music that put me off.
Here are some samples, including PCM and ADPCM variations:
http://simonowen.com/misc/sndcompare.zip (661K)
The ADPCM versions seem quite inconsistent, as the quantisation size
vary between blocks. I actually prefer the constant quality of the
22kHz 8-bit PCM instead.
Again, it depends what you plan to do with the recordings. Chances are
they're just uploaded to YouTube, where they video will usually suffer
more than the audio (~128kbps AAC) in transcoding.
I'm sticking with PCM for now, with an option to vary the quality.
MS-RLE has served me well on the video side, and is widely supported.
Si
-----------------------------------------
Mgr. Aleš Keprt, Ph.D.
private: [email protected], www.keprt.cz
office: Moravian College / Moravská vysoká škola Olomouc, [email protected]
