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Wave/Mp3 Recorder and Player (DIGICIII-Digic II)?

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Offline yvesson

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Re: Wave/Mp3 Recorder and Player (DIGICIII-Digic II)?
« Reply #30 on: 21 / August / 2008, 05:03:51 »
Mp3 player in camera have two main advantages. First AA bateries. You can buy them anywhere and can have many with you. Mp3 in cellphone don't give that and no one wants to be without phone. Second is memory card. In this days they are huge. Not many mp3 players have memory cards, so they have hard limit for capacity. Additionally one device is more comfortable than couple.

Just your own choice really, I don't have a cellphone at all, and don't wanna be without my camera ^^

Somehow I think playing mp3's would be a great feature, though I have the feeling I wouldn't use it.

Re: Wave/Mp3 Recorder and Player (DIGICIII-Digic II)?
« Reply #31 on: 06 / February / 2009, 10:18:40 »
I think the processor inside the cameras are too slow to decode regular MP3 files.

However, an existing source code for a MP3 player could probably be optimized to support only mono MP3 files encoded at a bitrate the camera supports.

For example, my A580 camera supports 11025 Hz mono sound, but probably there are better formats selectable. (well, 11025 mono 24-32kbps is actually mp2 already but that's not important)

The feature could be labeled as eBook reader, rather than mp3 player.

Regarding output, I think the Video out connector could be used. It's a regular jack with three wires, from which one is the audio and two are composite video or s-video.

CHDK would just need to simulate playback of a video in play mode or something like that.


Offline ewavr

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Re: Wave/Mp3 Recorder and Player (DIGICIII-Digic II)?
« Reply #32 on: 06 / February / 2009, 15:00:00 »
I think the processor inside the cameras are too slow to decode regular MP3 files.

Hmm, how about this: http://www.mikrocontroller.net/articles/ARM_MP3/AAC_Player ?
ARM7 @ 54 MHz can play any mp3 file using software-only decoding.

Re: Wave/Mp3 Recorder and Player (DIGICIII-Digic II)?
« Reply #33 on: 06 / February / 2009, 15:32:36 »
I don't know a lot about ARM architecture and I believe you if you say it would.

But let's assume that processor inside Powershot cameras is running at 72Mhz. In this case, it would probably mean that the camera would play this MP3 file but probably wouldn't have spare processor not even to update the display, so it would be pointless.
It's also unknown how much battery arm processors use when running at close to 100% all the time decoding mp3 files.

Probably a compromise would have to be made between processor usage and audio quality, like allowing only mono mp3 files (integrated speaker and video out is mono anyway)


Offline foofighter69

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Re: Wave/Mp3 Recorder and Player (DIGICIII-Digic II)?
« Reply #34 on: 16 / May / 2009, 16:34:39 »
The E in the ARM946E-S stands for enhanced DSP capabilities. I don't think mp3 listening would be a great shock for this processor.

Code: [Select]
Analysis of the processing stages in the MP3 algorithm
shows that in the critical front-end steps, which include
reading of the bit stream, Huffman decoding and inverse
quantization, the ARM RISC architecture has a performance
advantage over many DSP implementations. In addition,
the core can also be used to implement all of the complex
control tasks.

Forget MP3 - I'd be Delighted to Rec 1+hr of audio using existing onboard codecs
« Reply #35 on: 17 / September / 2009, 21:00:22 »
I would love to be able to record 1+hour of audio using existing onboard codecs. This would be very so much simpler to create, and yet would still have a lot of usefulness, so the cost/benefit ratio is much better than MP3. I think pushing the MP3 angle is destructive - sure, it is somewhat better, but it is obviously not triggering the interest of the developers.

So I would like to emphasize that a small tweak to extend the lengths of my cameras existing audio recording features should not be very hard, and would be immensely useful. Take my example below:

Extended audio recording is the feature I really miss from my Pentax Optio S4 - I was able to hold down the power button for 2 seconds, then it goes into audio mode. Then I could hit the shutter and it will record till battery or SD runs out - with display off that can be hours! It is so super handy for recording lectures or presentations or meetings. Sure, the onboard mic and the audio quality (8khz PCM) are not great, but for recording voice conversations it doesn't matter, and hey - I have a Dictaphone/voice recorder in my pocket!

Not all that many MP3 players have this option - at least not the MP3 players I know/own, so it is not simply a matter of "use a more appropriate/readily available device". And in response to the argument that "this is not really what a camera is for", I would say that it is now assumed that a camera's role is also to record video (and voice memos), so I am proposing a subset of this existing feature, not really a new feature.

And the clincher is that my Canon camera (a720) can already record audio (11khz, 8bit, mono (20kbps)), but the voice memo is cut off at 30 seconds, and the video comes with much larger file sizes and battery drain. So surely it would not be hard to extend the voice memo length, or make an option to record video that is is black (and ideally 1x1 pixels).

Extending voice memo would be preferable, and probably easier, though it might not play back onboard the camera. Hacking the video to record black may be not too hard, and there are already video recording hacks. Black video would also play back on board the camera. Ultra-Low-Res video might be harder to implement and might not play back on board the camera.

Maybe it could also be looked at like this:
Step    Feature                                                                        Difficulty             Benefit
1         Record longer audio using existing onboard codecs     Easy                  Very High
2         Play back camera-recorded audio                                 Easy-Moderate  Low-Medium
3         Play back third-party audio in onboard codec              Easy-Moderate  Medium-High
4         Play back third-party audio in other codec (MP3)        Hard                   Medium-High
5         Record audio in other codec (MP3)                              Hard                   Low

Looking at this breakdown, I have a few observations: each step could be done by itself and still provide value; step 1 definitely has the best cost/benefit ratio; step 5 only has a benefit of Low because I suspect the hardware will only support lower quality audio audio anyway which already has a small file size, so compressing it is not that important.

NOTE: I believe that my proposal is sufficiently different to the theme of this thread for it to also stand alone, so I have posted it at http://chdk.setepontos.com/index.php/topic,4227.0.html
« Last Edit: 17 / September / 2009, 21:02:44 by nosignal »

Re: Wave/Mp3 Recorder and Player (DIGICIII-Digic II)?
« Reply #36 on: 26 / November / 2012, 20:01:19 »
I'm surprised that no one has mentioned this, but optimized arm code for all codecs playing already exists, www.rockbox.org

What I want instead is playing movies on the camera :)  Actually, I've tried converting to mjpeg with the same parameters but they don't play.  I'm thinking that the camera is cheating and making a barely compliant stream and there's some advanced setting to make compatible encodings.

Re: Wave/Mp3 Recorder and Player (DIGICIII-Digic II)?
« Reply #37 on: 08 / March / 2013, 10:57:36 »
An option for CHDK to play SHORT wave files (which are small) could be useful. 

You could then write a script to have the camera speak shutter and aperature settings
at half shutter press.

Sound interesting?  Any takers?

-- Feral Boy

Utilizing built-in video code? -- Re: Wave/Mp3 Recorder and Player
« Reply #38 on: 30 / June / 2014, 16:34:10 »
Canon firmware can play videos. With sound :).

So, why not hooking up to this?

The user has to re-encode the audio to fit the audio-codec used for the videos. Then save that file to the SD-card (audio only, no video). Use chdk to call the canon-firmware-decoder to decode the audio, and play it.

If this is not possible, because the files have to have also video information (I don't know): Use lowest-possible-quality lowest-possible-resolution white or black frame (or embed album art) and play it as-is as video. And have CHDK just add some features which are comfortable for audio-player-use.

The conversion has to be done on the computer, on unix-systems it should be no too difficult to write a script which does that (using ffmpeg or mencoder for example), for windows users someone should write an .exe-file.

So that approach seems just more to design a good user interface for the camera (CHDK or scripts), and a good bash/python-script / windows/mac-programme to convert into canon-firmware-processable files (correct-codec-audio-only or video-with-minimal-quality-dummy-frames). Should be doable.
« Last Edit: 30 / June / 2014, 16:36:50 by oid_maps »
My cameras:
* Canon PowerShot:
  - A570 IS (Firmware 1.00E)
  - A2000 IS (Firmware 1.00C)
* Other manufacturers:
  - Pentax K10D (Firmware 1.31)

Re: Utilizing built-in video code? -- Re: Wave/Mp3 Recorder and Player
« Reply #39 on: 30 / June / 2014, 18:03:08 »
So, why not hooking up to this?
Should be doable.
Thing get done in CHDK because somebody wants to do them and has the skills and time to make it happen. So unless somebody volunteers to do something like this,  it just won't get done.  Sorry.
Ported :   A1200    SD940   G10    Powershot N    G16


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