Timecode over wireless aud

N

naavt

Well-known member
I'm not finding the way to send Timecode to my camera over wireless audio and will appreciate any assistance on this. Here's the details:

I Jam my Tascam HD-P2 with an iPad Movie Slate, connect my Sony UTX-B2 to Tascam's Line-Out and it doesn't show any AF/Peak response.

My intention is to send Timecode from the Tascam recorder through Sony's UTX-B2 to Sony's URX-P2 receiver connected to the TRS audio input on my Blackmagic camera.

I've tried to connect the iPad directly to camera and it records the Timecode signal from the Movie Slate just fine so the only issue here is finding how can I send Timecode from the Tascam over the Sony transmitter.

Thanks in advance.
 
David Jimerson said:
The UTX-B2 is an analogue transmitter; I don't see anything which suggests it CAN transmit timecode.
Click to expand...

Well… I assure you it can.

I plug the iPad Movie Slate to the transmitter and the receiver receives Timecode and can feed an audio channel with it without any hassle. I've imported a few seconds of video recording the iPad plus that channel audio, imported to Resolve and updated TC from audio and it's there. Every frame in sync with the iPad digital slate.

I've also tried to feed both the Tascam and the transmitter with an iPhone with Movie Slate (with a split TRS audio cable), and it works fine but in the end I would need my iPhone to continuously drive both with TC, or buy an iPod touch to do that without giving up my phone.

Because of that it would be great if I just could send TC from the Tascam over Line-Out audio to the transmitter.
 
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Tascam HD-P2. It has LTC in. It does not generate TC but can be jammed and I have Movie Slate app just for that.
 
naavt said:
Well... It cannot generate but I was under the impression that I could send TC embedded in one audio channel from the line outputs.
Click to expand...

Nope - TC is not embedded in the audio output. Without a dedicated timecode output on the recorder there's no way to send it anywhere. In a file based system such as the broadcast wave files produced by the Tascam there is no continuous linear timecode associated with the audio stream. The recorder's timecode clock places the timecode value for the first audio sample into the wave file header as part of the metadata. That's it, just that one reference point. There's no stream of timecode anywhere else in the file. The timecode for other locations in the file is calculated on the fly from the timestamp, the sample rate, and the number of samples played during playback. At no point is it part of the actual audio data stream.

Your jammed code provides the timecode reference for the audio. Photographing the numbers on the slate at the start of a shot provides the timecode reference for the video. Why do you feel you need to get a stream of LTC onto an audio channel in your video file? It's not really relevant in a file-based workflow.
 
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Hi Steve,

Good to ear from you. It's been a while (years actually), that we had this same conversation and I've been absent from the forum since. If you ask me I was thinking to send you a PM regarding the subject at hand since I remembered you to be an expert on this. Glad you stepped in.

Well… Starting at the end of your reply. My line of job is still the same as it was some years ago. I still shoot documentaries with a double system. Interviews are simple to sync because we (me and the sound director), can clap all the takes. The hassle is when we are shooting and recording as observers (which is often the case). In those circumstances we cannot clap every take and at the end of a shooting day we have 4, 5 or more hours of sound and video that is a pain to match in post.

That happens not only because the recorder and camera won't start at the same time but many times he's recording something that I'm not shooting, so I can end a day's work with 100 shots and he has 150 recorded files for instance. That's why we feel that Timecode can really help our post production workflow.

Anyway, an update. Because I couldn't retrieve TC from Line-outs (and now you gave me the reason why I couldn't), I've gone back to HD-P2 manual's again and found this:

"The possible audio Clock source values are: Internal - The audio clock is crystal-controlled and generated by the HD-P2. Use this only if the HD-P2 is to be the audio clock master in your system with its S/PDIF digital audio output set to synchronise other audio gear."

So.. For what I understand here the HD-P2 send out TC from its S/PDIF output. My first thought on this one is:

1. Jam the internal clock with Movie Slate
2. Run the S/PDIF out to a DAC http://www.ebay.co.uk/itm/Lindy-SPD...uting_CablesConnectors_RL&hash=item5660b4f25f and connect the other end to my Sony UTX-B2 transmiter.

Does it have a change of working this way?
 
naavt said:
Because I couldn't retrieve TC from Line-outs (and now you gave me the reason why I couldn't), I've gone back to HD-P2 manual's again and found this:

"The possible audio Clock source values are: Internal - The audio clock is crystal-controlled and generated by the HD-P2. Use this only if the HD-P2 is to be the audio clock master in your system with its S/PDIF digital audio output set to synchronise other audio gear."

So.. For what I understand here the HD-P2 send out TC from its S/PDIF output.
Click to expand...

That's not a Time Code clock. The master clock is what determines the actual sample rate and allows two (or more) devices to run at the same actual sample rate in order to avoid drift over time. So, it's what's dictating 44.1kHz or 48kHz or 96kHz, not TC value.
 
Alex H. said:
That's not a Time Code clock. The master clock is what determines the actual sample rate and allows two (or more) devices to run at the same actual sample rate in order to avoid drift over time. So, it's what's dictating 44.1kHz or 48kHz or 96kHz, not TC value.
Click to expand...

Bummer! So the only way to accomplish this is to have an iPhone/iPod touch with Movie Slate and a split audio cable feeding TC to both Tascam and Sony transmitter all the time?
 
The easiest solution here is to jam-sync each device and let it go in free-run. Then you don't have to have things constantly connected.

It's also good to re-jam everything periodically throughout the day.
 
Alex H. said:
The easiest solution here is to jam-sync each device and let it go in free-run. Then you don't have to have things constantly connected.

It's also good to re-jam everything periodically throughout the day.
Click to expand...


My blackmagic camera doesn't allow jam-sync but you're right. Probably the best bet is to jam-sync the Tascam from the iPhone Movie Slate and leave the iPhone connected to the audio in on the camera.
 
Others have said most of this but lets put it in one place.

TC for syncing was only used for analog transports. In the digital world the TC is just a time stamp at the start of the file. TC is no where close to accurate enough to sync digital streams, for that you need "word clock". Even with TC on analog recorders you needed BlackBurst to stay in sync with video.

SO there is no problem at all sending LTC (Linear Time Code) over an analog connection, wired or wireless.

But all it does is give everyone the same start number, it doesn't keep things in sync.

For the OP's situation I would go with Alex's solution. Jam sync everything periodically and you will know what files associate with each other. The files will not be actually in sync, though they might be close enough. Yes syncing things properly takes time. Doing most things correctly takes time. I see very few low budget projects where the production is actually in sync. They are almost always somewhere between 1/4 frame and 1 1/4 frames out. 1/4 frame is close enough generally, 1 1/4 is not.

Some of these errors may actually be built into the devices? The DVX100 out put audio 1 1/4 frames (approx. it varied with the camera) out of sync over firewire. So everything digitally transferred started out of sync. The point is that YOU really need to deal with (or at least check) sync in post no mater what you do in production.
 
Noiz2 said:
Others have said most of this but lets put it in one place.

TC for syncing was only used for analog transports. In the digital world the TC is just a time stamp at the start of the file. TC is no where close to accurate enough to sync digital streams, for that you need "word clock". Even with TC on analog recorders you needed BlackBurst to stay in sync with video.

SO there is no problem at all sending LTC (Linear Time Code) over an analog connection, wired or wireless.

But all it does is give everyone the same start number, it doesn't keep things in sync.

For the OP's situation I would go with Alex's solution. Jam sync everything periodically and you will know what files associate with each other. The files will not be actually in sync, though they might be close enough. Yes syncing things properly takes time. Doing most things correctly takes time. I see very few low budget projects where the production is actually in sync. They are almost always somewhere between 1/4 frame and 1 1/4 frames out. 1/4 frame is close enough generally, 1 1/4 is not.

Some of these errors may actually be built into the devices? The DVX100 out put audio 1 1/4 frames (approx. it varied with the camera) out of sync over firewire. So everything digitally transferred started out of sync. The point is that YOU really need to deal with (or at least check) sync in post no mater what you do in production.
Click to expand...

Thanks for your tips.
 
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