USB Audio Input??? - page 4 - Feature Requests - CHDK Forum  

USB Audio Input???

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Re: USB Audio Input???
« Reply #30 on: 23 / April / 2008, 17:44:54 »
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if only i could get my hands on one of those (being european,i've been denied getting the sdk by canon usa.by canon europe i didnt even get such reply-denial mail.darn.
Same here. I've requested it several times over the years without success.

I do have some of the older documentation though. After browsing it there are some interesting functions for creating memory streams and stuff. But I can't see any function that would allow uploading anything but pictures, so I don't know how the Digicanon uploader works.

Re: USB Audio Input???
« Reply #31 on: 23 / April / 2008, 18:42:19 »
>>here was something what could get me in to trouble :-) <<

canon have two protocoles for comunication computer-camera. PictBridge (PTP) and native canon prot.
The first allows only file transfer. the second makes remote-shooting and so.
« Last Edit: 23 / April / 2008, 19:26:07 by owerlord »

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Offline BB

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Re: USB Audio Input???
« Reply #32 on: 23 / April / 2008, 22:40:04 »
Just a suggestion out of left field...

Is there a protocol with a small digital recorder (of the quality/functions you need) where you could time sync with the Canon cameras?

It would keep the streams separate until they were joined in post production--but it could make alignment much easier.

The sync could either be a data stream (clock from/to recorder with usec accuracy) or even what is used many times with GPS systems--just an accurate clock pulse every 1 second--or something.

-Bill

Re: USB Audio Input???
« Reply #33 on: 24 / April / 2008, 07:54:20 »
@BB - Unfortunately, though your suggestion is a solution, it is exactly what I'm trying to avoid.

You return from a day of shooting your "soon to be Nobel Prize winning documentary" and you have 50 takes of video and 67 pieces of audio some of which match the video and some of which do not. You have to not only load everything in to the hard drive, but then you have to tie up the Avid or Final Cut or Premiere or whatever your NLE is while you load in every video stream into the timeline one at a time, and then load in each audio stream that might be the proper one and search for some synch point to align them. If it's not the right audio, you have to repeat the process slipping and sliding the audio until you find synch.

Clapboard, you say? Well there goes that shot that proves your point because you just scared off - the perpetrator, the rare bird, the tourist, the ..... pick one.

Ever try to synch up 3 horses hoofbeats on cobblestone, two birds in the woods, a crowd, etc, etc, etc..... using double system? It ain't fun!

Three hours later after finally synching everything and logging what audio goes with what video so you don't have to do all this again later, you might actually have the energy left to start editing.

As you can see, if you load your video into the timeline and it is already totally in sync with excellent quality audio you're editing immediately.

Nobel Prize, here we come!!
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Re: USB Audio Input???
« Reply #34 on: 24 / April / 2008, 08:08:47 »
And, while I responded to the above suggestion in the interest of providing general knowledge for those who may not know the reasons I am pursuing this, please, let's stay on the topic of the feature request, "USB Audio."

We do not want to start chasing other ideas and recommendations about ways to do audio recording in the field. Just how to get USB audio directly into a CANON camera's USB port.
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Re: USB Audio Input???
« Reply #35 on: 25 / April / 2008, 14:15:29 »
I'll be travelling over the next week, so a lack of participation will not mean a loss of interest, just a lack of connectivity.

By the time I return, I'm sure this problem will have been totally solved!  ::)

Ciao,

 
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Re: USB Audio Input???
« Reply #36 on: 05 / May / 2008, 21:13:41 »
Oh my! No ideas from anyone...?
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Offline BB

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Re: USB Audio Input???
« Reply #37 on: 05 / May / 2008, 23:16:44 »
Well, you did not like my idea...  :-X

In the end, this is probably a two step process... First would be to get the USB communications functional with CHDK. Second would be to figure out how to (at high speed) replace the microphone digital data stream with that of the the USB data stream.

As far as I know, nobody here (in CHDK land) has figured out the software interface for the USB controller (where the ports are, what they do, interrupts, DMA, Program I/O, etc.)...

If this is something you need--somebody--will have to dive into a camera and code to figure the whole thing out. May even need to sacrifice a camera to scope/probe the USB hardware to understand what is happening and identify the section(s) of camera code that communicate with the USB port.

In of itself--I can imagine getting control of the USB port is the next big break through the CHDK community is waiting for.

And, even once that is done, how to get an external data stream in at high speed (while video is also being processed) and connected to the digital audio stream will be another (probably large) project.

And even if (or when) part 1 is done, part 2 may not even be possible (especially at high quality sound bit rates).

I believe that this all started with a firmware upgrade from Canon for one of their earlier cameras--that was reverse engineered--to figure out the starting point for CHDK.

One of the old timers here may know if that code had debugging labels/symbol tables attached which could make the great USB hunt easier?

-Bill


Re: USB Audio Input???
« Reply #38 on: 08 / May / 2008, 10:18:02 »
Following up some ideas previously kicked around:

Using the software provided with the camera it is possible to both upload and download *.jpgs and *.wav files.

There are two methods of uploading *.jpgs - one places images on the SD card. The other places images in firmware for use on startup as custom "USER" choices.

There is one method of uploading *.wav files and that is to firmware.

These are custom sounds used for Start-up Sound, Operation Sound, Selftimer Sound and Shutter Sound.

There are three sounds in each location. The first one is fixed, but the second two are user definable.

It would appear then that there are at least 8 buffer locations available for temporary storage that speak directly to the USB Port.

In order to find these locations we compare dumps of the firmware before and after loading a custom sound. Let's say we just change the Start-up Sound for User 2. The only thing that should change between a before and after dump would be the data in the buffer used for User 2's Start-up Sound.

Following this procedure, we can find all eight available locations individually. While probably not as useful ultimately, we could also load the same sound into all eight locations and find them all at once with a single comparison run. This might make it easier to find the general address area and then go back and do one at a time since we now know where to look.

It would probably be possible to create a known waveform to use, like 1kHz tone, to make things even easier.
 
« Last Edit: 08 / May / 2008, 10:42:39 by cybercom »
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Offline PhyrePhoX

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Re: USB Audio Input???
« Reply #39 on: 08 / May / 2008, 10:27:18 »
by the way, using gphoto i am able to upload all kinds of files onto the camera (sd card), not only wav & jpg. this may be unrelated to your audio problem, however i figured i just point that out, it may be useful later.

 

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