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#120001 11/14/21 04:21 PM
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PhillHS Offline OP
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Hi all,

With the Dragon / CoCo driver.

Is there any way to control the format of tape output files? Currently they seem to be saved as WAV files, is there a way of saving them as CAS files?

Cheers.

Phill.

PhillHS #120002 11/14/21 05:25 PM
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WAV is the only format which MAME currently supports for saving cassette images. This is partly because MAME emulates cassette tape interfaces on a lower level than many other emulators. Decoding data from the serial bitstreams MAME is designed to output would be difficult at best, though it would likely be more tractable for CPU-to-tape-drive interfaces based on USARTs and such than purely bitbanged interfaces such as the ZX Spectrum ULA which provide a much wider latitude for highly nonstandard formats.

PhillHS #120003 11/14/21 05:57 PM
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You can easily convert the wav output to cas with several tools, like the ones listed here: https://archive.worldofdragon.org/index.php?title=Tape%5CDisk_Preservation

robcfg #120004 11/14/21 08:48 PM
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Originally Posted by robcfg
You can easily convert the wav output to cas with several tools, like the ones listed here: https://archive.worldofdragon.org/index.php?title=Tape%5CDisk_Preservation
Yeah I know, I was just trying to save a step smile

Cheers.

Phill.

PhillHS #120005 11/14/21 10:52 PM
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CAS is really a nightmarish format that really should not exist. Many of the CoCo/Dragon emulators patch the ROMs to emulate the cassette, resulting in a format that cannot be directly mapped to a waveform, but ends up in practice requires either partaking in the same hacks, or some processing step to essentially simulate the result of patching the ROMs.

At least this is what I remember when I first started working on the CoCo stuff two decades ago.

PhillHS #120006 11/14/21 11:16 PM
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The CAS file for Dragon/CoCo is just a bit dump, nothing else.

I proposed an extension to the format to the author of the XRoar emulator that consist on some data appended at the end of the CAS file (named CUE extension), so it's transparent for machines and emulator and allow for some better reconstruction of the wave.

So, the CAS format is dead simple.

robcfg #120007 11/14/21 11:57 PM
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Originally Posted by robcfg
The CAS file for Dragon/CoCo is just a bit dump, nothing else.

Are you sure? This page would seem to indicate that it can be just a bit dump, but it certainly seems to be capable of a bit more than that, which I suspect is part of the issue at hand: http://archive.worldofdragon.org/index.php?title=Tape%5CDisk_Preservation#CAS_File_Format

PhillHS #120008 11/15/21 01:02 AM
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I generally think that MAME should always output lossless formats; leave the conversions to an external tool afterwards.

Trying to reduce down tapes etc.to formats such as cas, tzx etc. has caused so many problems over the years due to ambiguity in the specifications, as well as features being added then dropped. This has resulted in different encoders producing different results, sometimes conflicting with the output of other encoders and giving us cases where no one decoder can decode everything. The knock-on effect of this is decoders flip-flopping between supporting the output of one piece of software and another.

There are there are just too many 'badly' encoded files out there without MAME contributing to that by also supporting such things as these custom output formats, again to our own interpretation of the specifications.

In most cases we would have been better off just keeping the wav files, and maybe using a lossless encoder such as FLAC on them.

The same happened with CDs; and floppy images; different software implementing things in different ways, often resulting in images that are only 100% compatible with the software they were created with, despite using 'standard' formats.

PhillHS #120010 11/15/21 04:39 AM
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I think the widespread homecomputer emulator file formats should be supported, else nobody will use MAME for them at all. But plain audio (WAV) version must be still there. This may be done through a plugin (possibly realtime-converting data like a unix-stream or such) to make the emulation internally see audio signals.

E.g. Atari XL datassette has a stereo tape head and could play speech/music from cassette during load of a program. E.g. cassette games by Europa played a long music track from cassette while loading. Some programs also started and stopped the tape to output speech (quiz questions and such) although this of course only worked in fixed order (you could not wind the tape through software). It would make sense to support such audio tracks through an additional MP3 file since WAV eats much disk space.

Last edited by =CO=Windler; 11/15/21 04:40 AM.

MAY THE SOFTWARE BE WITH YOU!

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Originally Posted by =CO=Windler
It would make sense to support such audio tracks through an additional MP3 file since WAV eats much disk space.

Ah, yes, because we live in 1999 and terabyte-sized drives are still a dream of the future.

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