08876: specpls2 and clones, cpc464 and clones, others with a monaural cassette device: Stereo recordings of tapes get their Right channel discarded

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
08876	Media Support	Minor	Always	Jun 19, 2024, 17:24	Jul 7, 2024, 02:09

Tester	ICEknight	View Status	Public	Platform	MAME (Official Binary)
Assigned To		Resolution	Open	OS	Windows 10/11 (64-bit)
Status [?]	Acknowledged			Driver	sinclair/spec128.cpp
Version	0.266	Fixed in Version		Build	64-bit
		Fixed in Git Commit		Github Pull Request #

Summary	08876: specpls2 and clones, cpc464 and clones, others with a monaural cassette device: Stereo recordings of tapes get their Right channel discarded
Description	Currently when loading real recordings of Stereo cassettes, MAME will only use the first track (Left channel) instead of mixing both. Some games for systems with Monaural tape decks were recorded only on one of the Left/Right channels and, since the Right channel is always discarded, the latter will refuse to load in MAME when playing back accurate recordings of them.
Steps To Reproduce	- Load specpls2 driver. - Load the attached test program that's only recorded on the Right channel (File manager - > Cassette). - Press enter to start the Tape Loader. - F2 to start tape. - It will fail to load.
Additional Information	Exceptions to this would be any systems which did read two separate tracks, such as the Atari 8 bit computers and the Sega AI.
Github Commit

Flags	Verified with Original
Regression Version
Affected Sets / Systems	specpls2 and clones, cpc464 and clones, others with a monaural cassette device

Attached Files	spectrum_plus_2_save_test.flac (734,665 bytes) Jun 19, 2024, 17:24 Uploaded by ICEknight Test Basic program recorded on the Right channel

No.22195 Robbbert Senior Tester Jun 20, 2024, 00:08	From what I recall, the reason for this is one channel would lag behind the other, creating an echo effect, and cause loading to almost always fail. Acknowledged for now.
No.22196 ICEknight Tester Jun 20, 2024, 13:28 edited on: Jul 6, 2024, 15:24	But mixing both channels shouldn't have anything lag behind if they play in unison... And sometimes it does make loading succeed when it fails otherwise.
No.22198 Haze Senior Tester Jun 23, 2024, 11:51	a stereo tape being read / played back as mono should not cause an echo, that's a MAME problem.
No.22216 ICEknight Tester Jul 6, 2024, 15:44 edited on: Jul 6, 2024, 15:48	Maybe the problem is that Stereo tape players actually split Monaural tracks in two in an anynchronous manner, in which case perhaps the user could just have a "Play channel: Mixed/Left/Right" selector in the Tape Control menu, when detecting a Stereo recording on an emulated Monaural deck?