[Module/5D3] SMPTE experiment, not usable

[stevefal]

Btw, I don't think inverting output will make-or-break decoding. A reader should be able to read it either way.

[g3gg0]

background:
when switching to a more "rectangular" waveform, i had to increase the sampling rate from 8000 Hz to 44100 Hz.
but with 25 fps and 44,1 kHz the number of samples per LTC bit is 44100 / 25 / 160 is 11.025 which is causing a small bit offset.
some problems may come from this, but i hoped its influence isnt that high.

plus i didnt store the last phase for the next frame which shouldnt matter if the parity would be correct (not the case if inversion is activated)
if anything goes wrong with parity, the next frame will start without any transition.

another thing is the frame rate.
for testing please switch to 25 fps and disable all inversion settings in the menu.
set the volume so high, that it doesnt overdrive your audio input.
the best would be 80% of max volume iirc.

[AnotherDave]

Are these instructions for yesterday's build, or are you putting together a new one?

[g3gg0]

were meant for the yesterday build.
just to make sure it runs under optimal condition.

(it is just hacked together in order to check if it is possible at all. so it is hardcoded for 25fps)

[AnotherDave]

It works!....  sorta!

I switched it to 25fps, and turned everything to off and I started to get a recognizable signal on TC Toolbox!  It was slightly garbled - maybe 2-3 times a second it would display random numbers... but this is definitely getting somewhere.

What can I do to give ya more information?

[Dannington]

I'll give this a go on Media Composer later on.

Will let you guys know.

[stevefal]

To be sure, in order to run exactly 25fps, I needed to switch my 5D3 to PAL, correct?

I did that and also got a few recognized frames per second. I've set my TC reader to 0 frames of freewheel, so it shows only actual frames read.

But at 25fps I still see missing or early/late transitions after the sync word.

[mageye]

For anyone that is interested there is a FREE application for OS X that can read SMPTE. I have been searching online for this for days now and I finally found a link that works.

http://mac.softpedia.com/dyn-postdownload.php?p=45721&t=4&i=1

Hope it helps people

[AnotherDave]

I've been looking for an application that can read a .wav SMPTE track, and embed the TC metadata to the other/corresponding audio tracks from the recorder... but I am not having any luck.

I personally own a Tascam DR-680.  It's no Sound Devices 788T, but the DR-680 usually all that I need for sound.  The downside is that it doesn't have embedded TC so I was planning on using 1 of the 6 audio tracks as the TC from the 5D3... but how to embed that TC to the other (up to) 5 tracks is the real question...

[stevefal]

.. but how to embed that TC to the other (up to) 5 tracks is the real question...

I don't know of an actual embedded timecode for audio files beyond a BWF timestamp or an LTC track. Doesn't the DR680 support 6-channel BWF and WAV?

Why would you want to add timecode to each of the tracks? Can't you drop the 6-channel file into your editor and use your new TC track to sync with video? Of course reading LTC with popular video editors is a problem by itself.

Here are some utilities that might help: http://www.studiodaily.com/2009/07/guide-to-broadcast-wave-file-software-utilities/

[AnotherDave]

I don't know of an actual embedded timecode for audio files beyond a BWF timestamp or an LTC track. Doesn't the DR680 support 6-channel BWF and WAV?

Why would you want to add timecode to each of the tracks? Can't you drop the 6-channel file into your editor and use your new TC track to sync with video? Of course reading LTC with popular video editors is a problem by itself.

Here are some utilities that might help: http://www.studiodaily.com/2009/07/guide-to-broadcast-wave-file-software-utilities/

The 680 does support 6-channel BWF! 

I have been doing all of my .dng conversion in Resolve, and really dig the TC syncing features in there.  Do you have a workflow for syncing a 6 channel BWF with a video track in resolve by any chance? :-)

[mageye]

OK Just thought that I would mention that I have managed to get the SMPTE Reader application (mentioned and linked above) to syncronise to a pre-generated SMPTE signal rendered into a WAV file playing from the Sounder Recorder Playback feature from ML.

I have NOT got it to sync with the generated SMPTE Output from the module YET but it's nice to know that once the signal is in the correct shape it is possible.

[stevefal]

Do you have a workflow for syncing a 6 channel BWF with a video track in resolve by any chance? :-)

I haven't done it but supposedly 9.0.3 supports syncing LTC from a video clip's audio track to LTC to/from a discreet audio track. So I assume that if you stripe your video and 6-channel audio files with the same TC during shooting, you should be able to use Resolve's new feature.

If this effort leads to ML video files with embedded LTC (after conversion), plus the LTC audio output during shooting, I'll be very happy.

[AnotherDave]

If this effort leads to ML video files with embedded LTC (after conversion), plus the LTC audio output during shooting, I'll be very happy.

I second that! :-)

[stevefal]

Actually I'm fuzzy on generating LTC alongside the video - unclear how valuable that would be. In need to understand RAW/DNG/CinemaDNG + second system workflow better.

[AnotherDave]

Ah!  Resolve has a setting to adjust TC from LTC... but it only works for audio that is embedded on video!

On a side note, the 680 records free run TC to BWF files...  shame it can't be synced!

g3ggo has been working to develop the new standard for raw_rec, *.mlv with the hopes to include TC into the metadata. 

[AnotherDave]

Apparently this will do the job!

http://www.videotoolshed.com/product/64/wavetobwf/3

[g3gg0]

this is more like an experiment.
here i assume that the video and audio hardware clock lines are definitely in sync.
this time i dont guess where the audio hardware is currently reading from, as it is too jumpy.

either this is the best solution, or it is the worst. not sure.
even if it is working fine from what you see, it is possible that it is not usable as clocks will drift and you lose frames somewhen etc

[AnotherDave]

With the only the 'Invert Parity' turned on, it counts to 10 seconds, and reset to zero...

Numbers seem fairly jumpy on the frames.

[g3gg0]

okay i reworked the bit banging code a bit.
here is the result. possible that it doesnt work at all, possible that it works perfect

[stevefal]

Still no lock for me. I ran it at 25fps, and I don't get one frame recognized. Also it doesn't sound exactly like time code. I'd have to look closer to see what's different.

If you could get it to generate TC from a specific start time, I could generate some matching timecode on my end, and then overlay the waveforms in an image so you can see the differences.

[g3gg0]

can you generate a waveform that starts to count from 00:00:00.000 with 25 fps inm color mode?
no user fields (date etc) if possible.

thanks

[g3gg0]

i disabled color frame flag here. the code just outputs time and the parity bit to guarantee the same phase on all frames.
maybe it is better?

[stevefal]

Here you go. This starts at 23:59:59:24 and rolls to 0 after the first frame: http://popspring.com/mldrop/SMPTE_TC_25FPS_0-10S.wav

[stevefal]

i disabled color frame flag here. the code just outputs time and the parity bit to guarantee the same phase on all frames.
maybe it is better?

This was the first that I've been able to read at all. One of my readers can pick up a frame every second or two, and the other has been able to pick up only one frame so far.