NBTV programme built and edited in Audacity

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NBTV programme built and edited in Audacity

Postby Colin-JB » Thu Aug 26, 2010 8:41 am

I wanted to create a custom test card and this led me to build about 30 seconds of NBTV editing in Audacity. For a first effort I'm pleased with it. So far using TBP and NBSC it plays well with no obvious sync problems.

The next stage will be to make a 10 minute programme to go with it but there is some planning to do first!

In the meantime I think I am going to try a colour version to see how the colour stands up...

Colin-JB
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Anim 1-5+silence.wav
The full 'intro' that could be used before any NBTV film
(5.15 MiB) Downloaded 813 times
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Postby dominicbeesley » Fri Aug 27, 2010 2:58 am

Looking good! How did you create the test cards they're good!

Depending on the colour format used you may need to only edit on odd frames. NBSC is usually ok for editing on a frame by frame basis so long as you record them all with the same filter options (otherwise the colour sub-carrier can be out of phase and you get colour glitches) I'm not sure whether CCNC needs to eb spliced on odd frames.

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Postby Klaas Robers » Fri Aug 27, 2010 4:20 am

No, CCNC can be edited frame by frame, as the number of samples in a frame is 3528 and that is an even number. However the editing must be done with a precision of 1 sample. If the frame has one sople more or less you will have a reversal of the ARB phase and the display will return to black and white for a few seconds.

The NBTV-CDs are edited even in black and white with a one sample precision, so it is not e real problem.
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Postby Colin-JB » Fri Aug 27, 2010 10:28 am

The test cards were created using a great program I found whilst searching for 'Test Card Maker'. You can find it here; http://www.oodletuz.fsnet.co.uk/soft/tcmaker.htm

The animation was done in 5 stages, each stage having a precise number of seconds that could be divided by two. I figured that there would be no sync issues if each segment ended on an exact frame. As 1 second was 12.5 frames it made sense to make the clips 2,4 or 6 seconds long and this worked.

I'm guessing that should I wish to have a 5 second clip, as the clip would end half way through a frame, the following clip would have to follow immediately on with the second half of the frame - very precise editing indeed. I will have a go with that at some point.

An interesting observation, when I came to add sound, I first started with the sound file and added the picture. The result was rubbish. The picture sunk in the middle then disappeared. When starting with the picture file then adding sound, it was fine. No idea why this should be.

With colour editing I have hit a small problem and I am sure it is to do with audacity. I load in my fine colour wav file that plays ok and then export to wav - like I did with the b/w ones. Play the newly saved file and the colour is all over the place! The best way to describe it would be to compare it to the beginning of a video tape where you have just gone over the previous recording and you have those 'ghost' colours floating about for a few seconds. It is clearly exporting wrongly for colour and I need to tweak a setting but I don't yet know which one!

Apart from that, the edit seemed ok so I will persevere and post my results when I have eliminated the odd colour problem!

Thanks Klaas, you answered my unspoken question before I even asked it! The samples per frame will be of huge use when I really get to grips with this!

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Postby dominicbeesley » Fri Aug 27, 2010 11:03 am

Hi Colin,

Aha, TCMaker is indeed good and easy to use - I've been using it to make some 405 line Testcards recently too...

You didn't say is it NTSC (NBSC) colour or CCNC (Video2NBTV):
NBSC will go funny if you're out by a sample but should recover within a frame or two.
CCNC should correct itself but I don't know if TBP autocorrects it though may these days.

An easier (cheating) way of editing is to edit the pictures together in something like windows movie maker and then create and AVI then you can record that in Video2NBTV or NBSCRecorder....not as gratifying though!

In the near future I'll try and make a video splicer that will allow you to put together a set of NBTV wav files and it will join them together with all the samples lined up correctly and the colour signals re-coded correctly... might be a while though!

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Postby Colin-JB » Fri Aug 27, 2010 11:31 am

I solved the colour problem - it was audacity. The sample format was 32 bit float. When set to 16 bit, all was well.

An easier (cheating) way of editing is to edit the pictures together in something like windows movie maker and then create and AVI then you can record that in Video2NBTV or NBSCRecorder


Thats sort of what I did.

For example; The first static test card, I designed in TCMaker and saved to JPG. Then in Windows explorer, I copied the file and pasted 25 times. I now have 26 identical images in my folder. Now 2 seconds are 25 frames but there is method to my madness... I found a program called photolapse 3, which takes jpg's and converts them to an avi with the fps of your choice. So load up all 26 images and set at 12.5 fps. Thing is, when you create movie, it ignores the first file in the list and starts the movie from the second! Hence having an bonus picture at the start.

I now have a 50 frame movie at 12.5 fps - 2 seconds long. I run that through Video2NBTV to get my wav. I now want a 6 second clip to allow time for initial sync, so using audacity I cut and paste it twice onto its end and save the new file. Now I have my 6 second static test card :D

I want to try NBSC but I dont think I have an encoder. In the players folder there is a program called scrape NBSC, but I cannot get it to work - some kind of buffer overload causes it to crash which is annoying.

If there is a different one to try, let me know the link and I'll give it a bash. One day I will have learnt some electronic skills and will understand how to build a colour televisor and I will want to try NBSC colour as well.

In the near future I'll try and make a video splicer that will allow you to put together a set of NBTV wav files and it will join them together with all the samples lined up correctly and the colour signals re-coded correctly... might be a while though!

Well I've still to download virtual dub so I can try Gary's plug in. Have the day off tomorrow like every Friday, looking after my son. Think I may park him in front of Cbeebies so I can get on with more NBTV related stuff!

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Postby dominicbeesley » Fri Aug 27, 2010 9:20 pm

Yes, get him entranced by Waybuloo and you enjoy yourself!

Re: ScrapeNBSC you have a PM!

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Postby Harry Dalek » Sat Aug 28, 2010 6:05 pm

Hi colin very good !!!
its on my hard drive now great work !
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Postby Colin-JB » Sat Sep 04, 2010 9:14 am

harry dalek wrote:its on my hard drive now great work !
harry


Would you like the colour version too?

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Postby cocolove » Sat Nov 27, 2010 8:31 pm

No, CCNC can be edited frame by frame, as the number of samples in a frame is 3528 and that is an even number. However the editing must be done with a precision of 1 sample. If the frame has one sople more or less you will have a reversal of the ARB phase and the display will return to black and white for a few seconds.

The NBTV-CDs are edited even in black and white with a one sample precision, so it is not e real problem.





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