DigitalCD 3.13

Hello,

DigitalCD 3.13 and the corresponding sources are available from the DigitalCD download page .

The TimVis 1.15 and Sonogram 1.08 plug-ins are available here
and here.

The main change, apart from bug fixes, is the handling of FFT in the DCDUtils module which provides better displays in the Sonogram plug-in.

Unfortunately the sub-centi-seconds version of OS_ReadMonotonicTime is still absent from RISC OS. This would have been nice since 100 FFTs(=lines)/second in Sonogram is too slow to show detailled variations in timbre and removing all limitations is just too fast on recent machines. The ability to limit to 200, 300, 400 or maybe 500 DDTs/second would have been useful.

Edit 05 April:
- I modified the DigitalCD.Run in the archived to disable logging and adjust the WimpSlot to run on older versions of the OS.
- Sonogram was updated to 1.09 so the delay between lines is now controllable in milliseconds.

Excellent! Thank you :-)

Well done on the update. A thought (after it was suggested on the Python thread) – would druck’s TimerMod help with the sub-centi-second timings?

Well I misspoke, instead OS_ReadMonotonicTime I should have said Wimp_PollIdle. The basic working of Sonogram at the moment is: perform an FFT, draw the corresponding line and as WimpPoll_Idle to call us back after x centiseconds. That is to say full-screen plugins take over the screen but multitask to let other applications (and DigitalCD) continue to work.

So yes, when I drop to 0 centiseconds I can turn to TimerMod to wait for a fraction of a centi-second before doing anything. A bit of a waste since other applications could use that wait time, but then again the other full-screen plugins use multiple screen banks and thus already waste time waiting for VSyncs to switch screen banks.

Is there any foreseeable possibility of DigitalCD supporting either AAC or WebM audio? I ask because that seems to be what YouTube streams these days. My downloader app is no longer showing MP3 or Vorbis.

For AAC, a while ago, I had a first shot at incorporating libfaad into the DiskSample module, so I could use it both for internet radios and KinoAmp but it has the bad habit of pushing whole work tables on the stack at every corners which isn’t very wise when using the system stack. I still have to want to give it another shot later.

With regards to WebM audio, I presume you mean the Opus codec. I haven’t looked into it yet.

it has the bad habit of pushing whole work tables on the stack at every corners

Yikes!

With regards to WebM audio, I presume you mean the Opus codec. I haven’t looked into it yet.

Yes. Looked it up so I now know the audio is Opus and the container is WebM (which looks like some derivation of Matroska).

Opus is completely open, see https://tools.ietf.org/html/rfc6716 which also contains a reference implementation in C (as a base64 encoded file!).
I’ll warn you though, it’s 150 pages and the maths kicks in early.

That being said, there are versions for hardware FP, and for fixed point on integer only systems, so there ought to be something that will work for RISC OS. ;-)

Sonogram updated to 1.09, uses TimerMod to offer finer speed control. See edit in the original post.