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Is timecode output by DVD players?

Hi, I want to extract timecode from a DVD player video output, and use it to trigger events and to control various loads. I plan to build a PIC based unit to do this, but I can't find out how widely available a timecode signal output might be across the extensive DVD player market.

Anyone know how often is timecode present on commercial DVD movies?

If it is available, and output by the DVD player, on which connector, S-Video or SCART, or both?

Is it VITC (vertical interval time code) - I have found a chip to decode this - ICS2008b

There are a few pro-sumer DVD players with RS232 ports, but even for these I can't determine whether a timecode signal is available. In any event I would prefer to use 'ordinary' players.

Thanks for any help.

J
Reply to
no-reply-john
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I would say, likely never. The DVD MPEG-2 data stream only includes the actual picture (plus overscan, of course). If there is any timing information in the analog signal output, then it is being inserted by the DVD player itself; it's not part of the software you're playing.

Reply to
larwe

I would be very surprised if any commercial DVD movies had it.

VITC is used primarily in analog-only recording systems or broadcasts. In digital recordings like DVD or mini-DV the timecodes are recorded as part of the binary data stream so there is no need to put them into the vertical blanking interval of the video.

Your best bet might be to try to extract a relative simestamp from the digital audio stream. If your DVD player can output raw audio through the SPDIF output (either optical or coaxial cable) then there might be a timecode in there. If it only outputs PCM or has no digital audio output at all then you're out of luck. I'm not even certain if any of the verious raw streams like AC3 or DTS would contain an absoulute timestamp. Start by looking at IEC61937 which describes how the raw audio streams are sent over SPDIF. Then check the standards that describe AC3 and DTS to see if the frames contain a timestamp. MPEG 1 Layer 2 frames do NOT contain timestamps in the headers so if you happen to get a DVD that uses only this audio format then you're also out of luck.

--Tom.

Reply to
Tom

Hi Tom, I was browsing the SPDIF spec, late last week, for something I'm working on and there is no obvious time stamp in it. It's a very simple protocol, Checkout CS8406 data sheet from Cirrus or ebu.ch for the official docs

I would suggest that the easiest(?) way would be via an RS232 control, pause the sequence to played, send play command, and count the frame pulses in the video (LM1881 etc). It may not be that accurate or repeatable . A bit like control track video editing, before LTC became popular

martin

Reply to
martin griffith

The SPDIF output from a CD player does typically include the subcode channels from the disc, one of which ( Q I think) includes the timecode - many years ago I made a box to extract and display it.

I just tried plugging this box into the SPDIF out on a DVD player, and even with an audio CD I don't get any time info - I suspect that as it's a DVD player it has more digital processing between the disk and the socket, and the subcode doesn't make it through - this may vary between players I suppose.

Reply to
Mike Harrison

from the disc, one of

extract and display it.

with an audio CD I don't

processing between the

between players I

Suppose I'll have to go back and re-read the specs.........

martin

Reply to
martin griffith

Thanks all for your suggestions. I'm currently looking at using a pro player with an RS232 port - that is as soon as I can find one in the UK :)

J
Reply to
no-reply-john

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