[Module/5D3] SMPTE experiment, not usable

[g3gg0]

i didnt understand - this one is generating codes that can be read without errors, or is it the one that generates at least a few readable frames?

[stevefal]

With the last module you posted, I could read a few frames, every few seconds. That module is the only one that I have been able to read at all. All previous modules you posted were not recognized as valid timecode by my reader.

[g3gg0]

this ojne outputs only zeroes.
and this the current time.

i changed the bit filling code a bit.

[stevefal]

I'm reading that one solid. You got it.

I'll have to do some experiments to see if it's as robust wrt signal level compared to my generators.

[AnotherDave]

You got it?! :-D

I can't try it out until tomorrow.

[AnotherDave]

Ok, I lied!  I had ten minutes so I tried it out, and BAMMM!!!

It is totally there!

Issues
1. It shuts off once you start recording.
2. If you start shooting with it on, then try to turn it back on again after you've stopped... it locks up the camera.

It doesn't really need to run while you're recording though.

[g3gg0]

these are no issues, as it is not designed to work with any video recording function yet.

[mageye]

First of all thanks g3gg0 for all your work. It is very much appreciated .

I have tested this repeatedly and my results are not so promising.

I am testing on the 5DMKII
I am using the latest nightly build (31302bbc6461 16th Aug.) (also a844c5e3a60e build) and have even 'restored ML defaults' (amongst other things).

To test it I am using the software SMPTE Reader on the Mac (OS X 10.8.4). I know this software is capable of reading the SMPTE signal because I have managed to read the signal (and synchronise) from a pre-striped WAV file playing from the camera.

To create the 'striped' WAV I used the MAX4Live object found here: http://cycling74.com/toolbox/smpte/

Interestingly when I tried today's provided smpte.mo file(s) ('current time' build) I got something the first time I tested it?

It did indeed pick up the current time and ran for a short time . After that, changing back and forth between Live View and 'normal' mode I was only getting occasional flashes on the SMPTE Reader application . Most of the time I am getting nothing .

I have tried turning off the camera in between tries and trying it with FPS override ON/OFF. I set the Canon Movie rec. size to 1920x1080@25 I have tried changing the FPS from 25FPS (just to try it). Also I have been trying different volume level settings and VSYNC too. It seems that the results are intermittent at the very best .

I have certainly not had it running reliably yet . It's a shame because it seems as though it's so close to working now .

I would like to know what settings are best likely to be able to create the syncronisation? I think I have tried many things and am willing to test further .

NOTE: Whilst testing I have been checking to see if the setup is capable of sending/receiving SMPTE by using my striped test WAV played back from the ML Sound Recorder 'Playback selected file' and that works every time and really doesn't have any problem synchronising at almost any volume level.

I would really like to see this thing working and I have a feeling that its getting close now.

Thanks again

[g3gg0]

@mageye:
the only thing the module was for, was testing to get audio sync.
neither stability nor features were in focus.
i just wanted to output a signal that is readable....

@all:
i added support to raw_rec and smpte to ouptut 100 smpte frames when recording starts.
here

it still outputs one frame, then a bit of silence, then frames again.
there is for sure a offset in buffers etc that will cause frame dropping and so on.
so its still an experiment.

[stevefal]

Another possibility that may have already been discussed is an electronic slate.

Instead of marking the head of the audio clip with SMPTE, mark it with spoken marker ID# and an electronic clap. The audio would be stitched together from short samples and triggered by a button (at any time) and optionally on record start:

  "Mark one three two .... BLIP"

The BLIP is a tone that lasts one frame and is synced with a synthesized marker frame in the video, that contains the text e.g. "Mark #132". Not sure how that could be implemented - pre-made RAW blocks?

I suggest mark numbers because time codes are longer and therefore less convenient. When the mark counter is reset, the numbers will be super short.

The video marker could include, say, 10 frames of blue and one frame of red corresponding to the BLIP. N frames makes it easier to find them when shuttling.

The audio fragments could be file-based for easy localization.

If this is interesting I'll offer to contribute professionally recorded audio samples in English, and testing. I could also contribute RAW source material for video markers if that was appropriate.

[stevefal]

To be clear, the idea of the slate system is that the camera would output the audio slate, and you would record it on a spare channel of your external recorder. In post you would then manually align audio to video using the markers, and then link or nest them as appropriate to keep them together. Of course it's not true sync, but it would be really useful as a poor man's tool.

[mageye]

@stevefal

The RAW record already makes a bleep sound when you record. I have already tested this. So far I have been using a real clapper board but then I decided to test the viability of just using the bleep and an external recorder. I found that if you align the blip one frame right of the beginning of the DNG sequence it synchronises. At least it did in the few tests that I have done. I am not sure how consistent (or accurate) the timing is for the bleep but it I did manage to get a pretty tight sync.

For my initial tests I recorded the clapper and aligned to the bleep to see how much offset there was (with the clapper). As I said, I found it to be about a frame to the right of the start of the video recording.

[stevefal]

Yep, so that part works. The auto-slate idea adds automatic clip identification in order to match audio-video content.

[mageye]

I am all for anything that makes sound synchronisation automatic or 'more automatic'. So I am not against your suggestions. Remember also that in the conventions for the MLV format there should/will be support for sound. It looks to me like, if what is proposed in the outline of the format comes to fruition, then full sound and synchronisation will be supported (to a high degree of accuracy too). I have faith. I look forward.

[AnotherDave]

Why can't we just Jam Sync the current time to an audio recorder?  This doesn't need to output during recording at all.  It just needs to provide a way to sync with the camera's time before you record...

I'm (hopefully) picking up a used Tascam HD-P2 today to test this out.

We would only need to be able to lock the TOD from the camera to the free run TC of the recorder... And this should be doing this already.

Shouldn't it?

[g3gg0]

this thread is about SMPTE...

forgot to add: disable audio in canon menu.

[stevefal]

I have had Canon audio disabled in all my attempts.

[stevefal]

this thread is about SMPTE...

Side chat in http://www.magiclantern.fm/forum/index.php?topic=7886

[g3gg0]

and does it work with raw_rec?

[stevefal]

and does it work with raw_rec?

Not for me. When I start recording, LTC output stops even though the display output continues. When I stop recording and go in to toggle LTC output, the camera UI freezes and I have to pull the battery.

[g3gg0]

you tried the version posted here?

@all:
i added support to raw_rec and smpte to ouptut 100 smpte frames when recording starts.
here

it still outputs one frame, then a bit of silence, then frames again.
there is for sure a offset in buffers etc that will cause frame dropping and so on.
so its still an experiment.

[stevefal]

Whoops no, I didn't try that. My readers take 2+ seconds to lock on this TC, but I'll try anyway...

[stevefal]

Neither module loads - "Linking failed"

5D3, Aug 21 build.

[EDIT] I tried my raw_rec build from Aug 21 instead of the one you provided in the zip, and the modules loaded.

It is working marginally, but I don't know what to expect. I set the number of frames to maximum, and once I get lock, my reader counts up as:

00:00:03:07
00:00:04:07
00:00:05:07
...

I get this exact sequence every time.

[AnotherDave]

Finally got my HD-P2 to pair with my DR-680 - the P2 can jam sync and send TC to the 680!

Haven't been able to get a signal to work from the module yet though.  Seems to be a bit of an issue using the headphone jack...

[AnotherDave]

Ok so there are a few weird issues I'm getting in relation to the headphone jack.

1. If it is plugged in on start-up, the module doesn't produce any sound.
2. If the jack is plugged in prior to starting the module, it will send it thru the speaker still.


I know this isn't a priority since this is all still experimental, just thought I'd mention...