Search found 70 matches

by MachineCode
Wed Jan 24, 2018 12:05 am
Forum: Support and Development
Topic: Synchronising video and audio
Replies: 16
Views: 2447

Re: Synchronising video and audio

Thanks guys. It is a big help to talk these issues through to clear up how it all fits together in a framework like love2d. I know a bit about digital audio because I designed one of the first Digital Audio Dubber systems when the studios moved away from mag tape. That was more of an embedded design...
by MachineCode
Tue Jan 23, 2018 10:31 pm
Forum: Support and Development
Topic: Synchronising video and audio
Replies: 16
Views: 2447

Re: Synchronising video and audio

@pgimeno thanks for that. A PID with long time constant is a good solution provided that snd:setPitch is reasonably low overhead. I really don't know what the low level audio machinery looks like in a PC, but I suppose there is fine grain control over the sample rate so it's just changing a register...
by MachineCode
Tue Jan 23, 2018 2:49 pm
Forum: Support and Development
Topic: Synchronising video and audio
Replies: 16
Views: 2447

Re: Synchronising video and audio

Yes - sorry, ppm is a hw engineer term that means parts per million. Crystals are typically 20ppm, so even though that is very close to perfect, if the video frame rate and the audio sample rate are generated by different xtals, then you will get long term drift. Suppose your sample rate is 44.1KHz....
by MachineCode
Tue Jan 23, 2018 12:07 pm
Forum: General
Topic: ZeroBrane Studio Lua IDE v1.70 is released
Replies: 5
Views: 2331

Re: ZeroBrane Studio Lua IDE v1.70 is released

What is the best way to set up ZB so I can select the nightly-build of 0.11 as an alternative to stable 0.10.2? Ideally the 0.11 would appear in the project interpreter option so 0.11 can be used on a project by project basis.
by MachineCode
Tue Jan 23, 2018 11:41 am
Forum: Support and Development
Topic: Synchronising video and audio
Replies: 16
Views: 2447

Synchronising video and audio

This is probably a question for Zorg. I am generating video frames with audio to be played simultaneously. The audio will be queued based on 60hz frames from the draw function. So, given the sample rate, can I rely on the SR * 1/60 sample count to not slowly slip out of sync with the video frame rat...
by MachineCode
Sat Jan 13, 2018 5:44 am
Forum: Support and Development
Topic: Image:refresh and Image:replacePixels in 0.11
Replies: 0
Views: 820

Image:refresh and Image:replacePixels in 0.11

I am working on a pixel drawing engine that uses 16bit instructions to draw stuff on an imageData which then updates the image in VRAM for drawing on the screen. A lot of the drawing could be done on a canvas, however using mapPixel to change colors and similar pixel operations would need some trick...
by MachineCode
Mon Aug 21, 2017 12:16 am
Forum: Support and Development
Topic: Playing a segment of audio
Replies: 7
Views: 1690

Re: Playing a segment of audio

Thanks again zorg. I think I have enough to start playing around with this now.
by MachineCode
Sun Aug 20, 2017 3:51 pm
Forum: Support and Development
Topic: Playing a segment of audio
Replies: 7
Views: 1690

Re: Playing a segment of audio

OK, so that means you could continuously synthesise audio using a single queueableSource and use a set of SoundData buffers in a round robin configuration to receive the output of your generator using setSample. These buffers would be refilled, then tacked on to the queue for the source to play. In ...
by MachineCode
Sun Aug 20, 2017 4:45 am
Forum: Support and Development
Topic: Playing a segment of audio
Replies: 7
Views: 1690

Re: Playing a segment of audio

Thanks zorg. Is there a link to the details of queuable source? One of the other things I want to try is generating a sound from a parametric descriptor held in a table or maybe generated by procedure. This may result in sample data of arbitrary length. Using 0.10, for each instance I could make a n...
by MachineCode
Sat Aug 19, 2017 8:05 am
Forum: Support and Development
Topic: Playing a segment of audio
Replies: 7
Views: 1690

Playing a segment of audio

Just a question about audio and the Source:play(). Is there any way to play a section from one point to another? I am thinking of a sound effects library in a single source that has a lookup table of start and end for each effect. I can see that using a :seek(start) then :play() and a timer activate...