Saturday, December 7, 2013

Re: [Avid-L2] Re: Is it I or is it P?

 

My wife just saw this and said 'see you're not the only one who worries about these things '...

Then she mumbled something under her breath that she would not repeat.

Mike



On 8 Dec, 2013, at 11:54 am, "johnrobmoore" <bigfish@pacbell.net> wrote:

 

Now that you mention it I used my waveform on the Tri-Level sync generator to view the broad pulses on a Tek 1750 a few years back. It was kind of a kludge but I could see how a true progressive Tri Level sync one set of broad pulses per frame. A Psf Tri Level was two sets of broad pulses per frame and a 1080i Tri Level was two sets of broad pulses with twice the number of broad pulses at half the duration judging by the look of things. I perhaps jumped to an incorrect conclusion that the same sync structure carried over to the sync signals in the HDSDI stream. I could not use my analogue scope to see the sync pulses of an SDI stream so I may be miss speaking. I thought I had also looked up the Vertical Sync structure in a Broadcast Engineering book too but I will have to double check.

When I was doing my tests I was trying to check that the Tri Level was locked to house black which I could see by referencing the 1750 to house black and looking for drift when set to external sync. The other thing I was looking for was how monitors know to display the various signal types they are receiving with their on screen displays and how a scope knows the difference between Psf and I. I figured the same differences I saw in the Tri Level sync must occur in the SDI stream which was what allowed the scopes and monitors to determine the type of signal they are receiving. I'm at work now but I will check my book at home to see if I can find it there.

If it's not the sync pulses in the HDSDI stream what is it that identifies the signal type? Perhaps I'm missing the obvious.

--- In Avid-L2@yahoogroups.com, Bogdan Grigorescu <bogdan_grigorescu@...> wrote:
>
> 'In the HDSDI stream the vertical broad pulses for Psf are twice the duration of those for interlace for a total of 5 and in interlace there are 10 broad pulses'
> Any reference to backup this statement John? 
>
> To the best of my knowledge the fields and segments are absolutely identical, including the blanking intervals(H and V), as described in the standard: http://read.pudn.com/downloads160/ebook/723748/s274m.pdf
>
> BG
> http://www.finale.tv
>
>
>
> ________________________________
> From: johnrobmoore <bigfish@...>
> To: Avid-L2@yahoogroups.com
> Sent: Saturday, December 7, 2013 6:16 PM
> Subject: [Avid-L2] Re: Is it I or is it P?
>
>
>
>  
> When you originally transcoded in the 25P project did you check how Avid had interpreted the field motion of the ama'd clips? Avid does a poor job of properly estimating the field motion. A lot of time it chooses default which isn't always correct. Job is correct that electronically i and psf are basically the same except there is temporal displacement in i media that isn't there in psf media. The difference is in how it is flagged. In the HDSDI stream the vertical broad pulses for Psf are twice the duration of those for interlace for a total of 5 and in interlace there are 10 broad pulses.
>
> I'm wondering if when you ama'd for the original transcode if you manually set the clips field motion to interlace if Avid would then chuck out the second Psf of the frame and double the first. In essence halving the vertical resolution. Similar to motion adapters choosing one field over both field. Worth a try just for the fun of it.
>
> --- In Avid-L2@yahoogroups.com, "Job ter Burg (L2B)" <Job_L2@> wrote:
> >
> >
> > It makes perfect sense.
> >
> > If you have 50i footage and you store it as P, you are in essence folding both fields (1920x540 x2) into a single frame (1920x1080 x1).
> >
> > If you open that footage in a 1080i project, the field stepping command will let you step from one field to the next, where a field is nothing more and nothing less than half of the lines of any frame.
> >
> > Transcoding to P doesn't make it progressive.
> >
> > I or P, both are stored as a frame, but they are flagged differently.
> >
> > J
> >
> > On 7 dec. 2013, at 18:48, Roger <rogershuff@> wrote:
> > >
> > > Came a cross a weird thing (well, maybe not if someone knows the answer). I had a card full of 1080i/50 footage from a Panasonic camera. For a rough edit, I decided to transcode to DNxHD36 (P) to keep the file sizes down. I set the Project format to 1080/25P and transcoded everything I needed. I then happened to examine some of this transcoded footage in a 1080i/50 format project, at full quality. I was able to step through field by field and both fields are still there. This is a dance studio so lots of movement - and I'm not just seeing the nudging up and down of the image that you usually get with progressive footage viewed in an interlaced project. It looks just like interlaced would. Am I mad? Symphony 6.0.4 on Mac OS 10.7.5.
> >
>

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Re: [Avid-L2] Mac Pro for sale -

 


On Dec 7, 2013, at 3:28 PM, Greg Huson wrote:

> Ok, i do have one other surplus machine - a 4-core first-gen intel that won't run the 64bit OS.  So, if your boat is floating away, or if you want to run FCP like you did in 2001 (?) I'll make you a great deal on THAT computer!

I shrug:

Sorry, I already have one of those . . . . . .  ;(

Dennis Degan, Video Editor-Consultant-Knowledge Bank
    NBC Today Show, New York


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[Avid-L2] Re: Is it I or is it P?

 

This document shows the image on page 8 of the difference between progressive and interlace, no mention of Psf that I have found. This part I recall seeing on my scope tests. I will have to check my gen 10 output at home for the Psf Tri Level. It has two sets of broad pulses just like the interlace does but what I remember seeing was broad pulses the duration of what this document shows for progressive, 5 pulses x 2 per frame. It's been a while but this has really stuck in my mind.

My current project is 1080 23.98 and the Tek shows 1080sf 23.98. Switching the project to 720P/23.976 and the scope reads 720p 59.94 which makes sense because there is no such thing as 720P/23.98 in the HDSDI spec. I'll have to try the other project types at a later time.

Tektronix Sync Document:

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&cad=rja&ved=0CEMQFjAE&url=http%3A%2F%2Fwww.tek.com%2Fdl%2F20W_18580_0_0.pdf&ei=PRCkUrGDKo_CoATYlICYAw&usg=AFQjCNEa9CqMShfIp9ghXxPRdC3o2yw2PQ&bvm=bv.57752919,d.cGU

--- In Avid-L2@yahoogroups.com, Bogdan Grigorescu <bogdan_grigorescu@...> wrote:
>
> Try the following test: 
> -send the following signals to your Tek HDSDI rasterizer : 23.98psF, 25psF, 29.97psF, 50i, 59.94i
> -write down the reported video format for each one of these and tell us the results
>
> And as I said, there are absolutely no differences between the digital, analog and tri-level sync representation between interlaced and segmented frame(they are actually referred as 'interlaced/segmented frame' throughout the SMPTE274 standard) 
>
> BG
> http://www.finale.tv
>
>
>
>
> ________________________________
> From: johnrobmoore <bigfish@...>
> To: Avid-L2@yahoogroups.com
> Sent: Saturday, December 7, 2013 9:47 PM
> Subject: [Avid-L2] Re: Is it I or is it P?
>
>
>
>  
> I do know in my engineering book it showed tri level sync as part of the HD video signal both H interval and V interval have tri level sync pulses in them. VPID was mentioned in the Tek seminar I attend a while back. My initial curiosity was when I saw the Kona 3 control panel indicating the type of sync that was connected to the unit. In the case of Tri Level sync is there a VPID? I wouldn't think so but the Kona knows what it is getting in the way of sync. It's been a while but IIRC it recognized differing types of Tri Level. Assuming I am recalling correctly that would indicate that the differences I saw on the 1750 scope would be the means by which the Kona control panel is deciding the type of sync signal it is receiving.
>
> Am I incorrect that an HD signal matching the same type of Tri Level signal would have the same Tri Level sync signals? I don't know why it wouldn't but ever since things went digital and I can't see the sync interval on most waveforms I'm not able to play along like I could in the analogue days. I do remember that Harris added the ability to view the sync interval on their wave forms but I haven't played with one of those for a few years since I saw it at NAB.
>
> --- In Avid-L2@yahoogroups.com, Bogdan Grigorescu <bogdan_grigorescu@> wrote:
> >
> > 'If it's not the sync pulses in the HDSDI stream what is it that identifies the signal type?'
> > VPID - video payload identifier - SMPTE352
> >
> > BG
> > http://www.finale.tv
> >
> >
> >
> > ________________________________
> > From: johnrobmoore <bigfish@>
> > To: Avid-L2@yahoogroups.com
> > Sent: Saturday, December 7, 2013 8:54 PM
> > Subject: [Avid-L2] Re: Is it I or is it P?
> >
> >
> >
> >  
> > Now that you mention it I used my waveform on the Tri-Level sync generator to view the broad pulses on a Tek 1750 a few years back. It was kind of a kludge but I could see how a true progressive Tri Level sync one set of broad pulses per frame. A Psf Tri Level was two sets of broad pulses per frame and a 1080i Tri Level was two sets of broad pulses with twice the number of broad pulses at half the duration judging by the look of things. I perhaps jumped to an incorrect conclusion that the same sync structure carried over to the sync signals in the HDSDI stream. I could not use my analogue scope to see the sync pulses of an SDI stream so I may be miss speaking. I thought I had also looked up the Vertical Sync structure in a Broadcast Engineering book too but I will have to double check.
> >
> > When I was doing my tests I was trying to check that the Tri Level was locked to house black which I could see by referencing the 1750 to house black and looking for drift when set to external sync. The other thing I was looking for was how monitors know to display the various signal types they are receiving with their on screen displays and how a scope knows the difference between Psf and I. I figured the same differences I saw in the Tri Level sync must occur in the SDI stream which was what allowed the scopes and monitors to determine the type of signal they are receiving. I'm at work now but I will check my book at home to see if I can find it there.
> >
> > If it's not the sync pulses in the HDSDI stream what is it that identifies the signal type? Perhaps I'm missing the obvious.
> >
> > --- In Avid-L2@yahoogroups.com, Bogdan Grigorescu <bogdan_grigorescu@> wrote:
> > >
> > > 'In the HDSDI stream the vertical broad pulses for Psf are twice the duration of those for interlace for a total of 5 and in interlace there are 10 broad pulses'
> > > Any reference to backup this statement John? 
> > >
> > > To the best of my knowledge the fields and segments are absolutely identical, including the blanking intervals(H and V), as described in the standard: http://read.pudn.com/downloads160/ebook/723748/s274m.pdf
> > >
> > > BG
> > > http://www.finale.tv
> > >
> > >
> > >
> > > ________________________________
> > > From: johnrobmoore <bigfish@>
> > > To: Avid-L2@yahoogroups.com
> > > Sent: Saturday, December 7, 2013 6:16 PM
> > > Subject: [Avid-L2] Re: Is it I or is it P?
> > >
> > >
> > >
> > >  
> > > When you originally transcoded in the 25P project did you check how Avid had interpreted the field motion of the ama'd clips? Avid does a poor job of properly estimating the field motion. A lot of time it chooses default which isn't always correct. Job is correct that electronically i and psf are basically the same except there is temporal displacement in i media that isn't there in psf media. The difference is in how it is flagged. In the HDSDI stream the vertical broad pulses for Psf are twice the duration of those for interlace for a total of 5 and in interlace there are 10 broad pulses.
> > >
> > > I'm wondering if when you ama'd for the original transcode if you manually set the clips field motion to interlace if Avid would then chuck out the second Psf of the frame and double the first. In essence halving the vertical resolution. Similar to motion adapters choosing one field over both field. Worth a try just for the fun of it.
> > >
> > > --- In Avid-L2@yahoogroups.com, "Job ter Burg (L2B)" <Job_L2@> wrote:
> > > >
> > > >
> > > > It makes perfect sense.
> > > >
> > > > If you have 50i footage and you store it as P, you are in essence folding both fields (1920x540 x2) into a single frame (1920x1080 x1).
> > > >
> > > > If you open that footage in a 1080i project, the field stepping command will let you step from one field to the next, where a field is nothing more and nothing less than half of the lines of any frame.
> > > >
> > > > Transcoding to P doesn't make it progressive.
> > > >
> > > > I or P, both are stored as a frame, but they are flagged differently.
> > > >
> > > > J
> > > >
> > > > On 7 dec. 2013, at 18:48, Roger <rogershuff@> wrote:
> > > > >
> > > > > Came a cross a weird thing (well, maybe not if someone knows the answer). I had a card full of 1080i/50 footage from a Panasonic camera. For a rough edit, I decided to transcode to DNxHD36 (P) to keep the file sizes down. I set the Project format to 1080/25P and transcoded everything I needed. I then happened to examine some of this transcoded footage in a 1080i/50 format project, at full quality. I was able to step through field by field and both fields are still there. This is a dance studio so lots of movement - and I'm not just seeing the nudging up and down of the image that you usually get with progressive footage viewed in an interlaced project. It looks just like interlaced would. Am I mad? Symphony 6.0.4 on Mac OS 10.7.5.
> > > >
> > >
> >
>

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Re: [Avid-L2] Re: Is it I or is it P?

 

Try the following test: 
-send the following signals to your Tek HDSDI rasterizer : 23.98psF, 25psF, 29.97psF, 50i, 59.94i
-write down the reported video format for each one of these and tell us the results

And as I said, there are absolutely no differences between the digital, analog and tri-level sync representation between interlaced and segmented frame(they are actually referred as 'interlaced/segmented frame' throughout the SMPTE274 standard) 

BG



From: johnrobmoore <bigfish@pacbell.net>
To: Avid-L2@yahoogroups.com
Sent: Saturday, December 7, 2013 9:47 PM
Subject: [Avid-L2] Re: Is it I or is it P?

 
I do know in my engineering book it showed tri level sync as part of the HD video signal both H interval and V interval have tri level sync pulses in them. VPID was mentioned in the Tek seminar I attend a while back. My initial curiosity was when I saw the Kona 3 control panel indicating the type of sync that was connected to the unit. In the case of Tri Level sync is there a VPID? I wouldn't think so but the Kona knows what it is getting in the way of sync. It's been a while but IIRC it recognized differing types of Tri Level. Assuming I am recalling correctly that would indicate that the differences I saw on the 1750 scope would be the means by which the Kona control panel is deciding the type of sync signal it is receiving.

Am I incorrect that an HD signal matching the same type of Tri Level signal would have the same Tri Level sync signals? I don't know why it wouldn't but ever since things went digital and I can't see the sync interval on most waveforms I'm not able to play along like I could in the analogue days. I do remember that Harris added the ability to view the sync interval on their wave forms but I haven't played with one of those for a few years since I saw it at NAB.

--- In Avid-L2@yahoogroups.com, Bogdan Grigorescu <bogdan_grigorescu@...> wrote:
>
> 'If it's not the sync pulses in the HDSDI stream what is it that identifies the signal type?'
> VPID - video payload identifier - SMPTE352
>
> BG
> http://www.finale.tv
>
>
>
> ________________________________
> From: johnrobmoore <bigfish@...>
> To: Avid-L2@yahoogroups.com
> Sent: Saturday, December 7, 2013 8:54 PM
> Subject: [Avid-L2] Re: Is it I or is it P?
>
>
>
>  
> Now that you mention it I used my waveform on the Tri-Level sync generator to view the broad pulses on a Tek 1750 a few years back. It was kind of a kludge but I could see how a true progressive Tri Level sync one set of broad pulses per frame. A Psf Tri Level was two sets of broad pulses per frame and a 1080i Tri Level was two sets of broad pulses with twice the number of broad pulses at half the duration judging by the look of things. I perhaps jumped to an incorrect conclusion that the same sync structure carried over to the sync signals in the HDSDI stream. I could not use my analogue scope to see the sync pulses of an SDI stream so I may be miss speaking. I thought I had also looked up the Vertical Sync structure in a Broadcast Engineering book too but I will have to double check.
>
> When I was doing my tests I was trying to check that the Tri Level was locked to house black which I could see by referencing the 1750 to house black and looking for drift when set to external sync. The other thing I was looking for was how monitors know to display the various signal types they are receiving with their on screen displays and how a scope knows the difference between Psf and I. I figured the same differences I saw in the Tri Level sync must occur in the SDI stream which was what allowed the scopes and monitors to determine the type of signal they are receiving. I'm at work now but I will check my book at home to see if I can find it there.
>
> If it's not the sync pulses in the HDSDI stream what is it that identifies the signal type? Perhaps I'm missing the obvious.
>
> --- In Avid-L2@yahoogroups.com, Bogdan Grigorescu <bogdan_grigorescu@> wrote:
> >
> > 'In the HDSDI stream the vertical broad pulses for Psf are twice the duration of those for interlace for a total of 5 and in interlace there are 10 broad pulses'
> > Any reference to backup this statement John? 
> >
> > To the best of my knowledge the fields and segments are absolutely identical, including the blanking intervals(H and V), as described in the standard: http://read.pudn.com/downloads160/ebook/723748/s274m.pdf
> >
> > BG
> > http://www.finale.tv
> >
> >
> >
> > ________________________________
> > From: johnrobmoore <bigfish@>
> > To: Avid-L2@yahoogroups.com
> > Sent: Saturday, December 7, 2013 6:16 PM
> > Subject: [Avid-L2] Re: Is it I or is it P?
> >
> >
> >
> >  
> > When you originally transcoded in the 25P project did you check how Avid had interpreted the field motion of the ama'd clips? Avid does a poor job of properly estimating the field motion. A lot of time it chooses default which isn't always correct. Job is correct that electronically i and psf are basically the same except there is temporal displacement in i media that isn't there in psf media. The difference is in how it is flagged. In the HDSDI stream the vertical broad pulses for Psf are twice the duration of those for interlace for a total of 5 and in interlace there are 10 broad pulses.
> >
> > I'm wondering if when you ama'd for the original transcode if you manually set the clips field motion to interlace if Avid would then chuck out the second Psf of the frame and double the first. In essence halving the vertical resolution. Similar to motion adapters choosing one field over both field. Worth a try just for the fun of it.
> >
> > --- In Avid-L2@yahoogroups.com, "Job ter Burg (L2B)" <Job_L2@> wrote:
> > >
> > >
> > > It makes perfect sense.
> > >
> > > If you have 50i footage and you store it as P, you are in essence folding both fields (1920x540 x2) into a single frame (1920x1080 x1).
> > >
> > > If you open that footage in a 1080i project, the field stepping command will let you step from one field to the next, where a field is nothing more and nothing less than half of the lines of any frame.
> > >
> > > Transcoding to P doesn't make it progressive.
> > >
> > > I or P, both are stored as a frame, but they are flagged differently.
> > >
> > > J
> > >
> > > On 7 dec. 2013, at 18:48, Roger <rogershuff@> wrote:
> > > >
> > > > Came a cross a weird thing (well, maybe not if someone knows the answer). I had a card full of 1080i/50 footage from a Panasonic camera. For a rough edit, I decided to transcode to DNxHD36 (P) to keep the file sizes down. I set the Project format to 1080/25P and transcoded everything I needed. I then happened to examine some of this transcoded footage in a 1080i/50 format project, at full quality. I was able to step through field by field and both fields are still there. This is a dance studio so lots of movement - and I'm not just seeing the nudging up and down of the image that you usually get with progressive footage viewed in an interlaced project. It looks just like interlaced would. Am I mad? Symphony 6.0.4 on Mac OS 10.7.5.
> > >
> >
>



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[Avid-L2] Re: Is it I or is it P?

 

I do know in my engineering book it showed tri level sync as part of the HD video signal both H interval and V interval have tri level sync pulses in them. VPID was mentioned in the Tek seminar I attend a while back. My initial curiosity was when I saw the Kona 3 control panel indicating the type of sync that was connected to the unit. In the case of Tri Level sync is there a VPID? I wouldn't think so but the Kona knows what it is getting in the way of sync. It's been a while but IIRC it recognized differing types of Tri Level. Assuming I am recalling correctly that would indicate that the differences I saw on the 1750 scope would be the means by which the Kona control panel is deciding the type of sync signal it is receiving.

Am I incorrect that an HD signal matching the same type of Tri Level signal would have the same Tri Level sync signals? I don't know why it wouldn't but ever since things went digital and I can't see the sync interval on most waveforms I'm not able to play along like I could in the analogue days. I do remember that Harris added the ability to view the sync interval on their wave forms but I haven't played with one of those for a few years since I saw it at NAB.

--- In Avid-L2@yahoogroups.com, Bogdan Grigorescu <bogdan_grigorescu@...> wrote:
>
> 'If it's not the sync pulses in the HDSDI stream what is it that identifies the signal type?'
> VPID - video payload identifier - SMPTE352
>
> BG
> http://www.finale.tv
>
>
>
> ________________________________
> From: johnrobmoore <bigfish@...>
> To: Avid-L2@yahoogroups.com
> Sent: Saturday, December 7, 2013 8:54 PM
> Subject: [Avid-L2] Re: Is it I or is it P?
>
>
>
>  
> Now that you mention it I used my waveform on the Tri-Level sync generator to view the broad pulses on a Tek 1750 a few years back. It was kind of a kludge but I could see how a true progressive Tri Level sync one set of broad pulses per frame. A Psf Tri Level was two sets of broad pulses per frame and a 1080i Tri Level was two sets of broad pulses with twice the number of broad pulses at half the duration judging by the look of things. I perhaps jumped to an incorrect conclusion that the same sync structure carried over to the sync signals in the HDSDI stream. I could not use my analogue scope to see the sync pulses of an SDI stream so I may be miss speaking. I thought I had also looked up the Vertical Sync structure in a Broadcast Engineering book too but I will have to double check.
>
> When I was doing my tests I was trying to check that the Tri Level was locked to house black which I could see by referencing the 1750 to house black and looking for drift when set to external sync. The other thing I was looking for was how monitors know to display the various signal types they are receiving with their on screen displays and how a scope knows the difference between Psf and I. I figured the same differences I saw in the Tri Level sync must occur in the SDI stream which was what allowed the scopes and monitors to determine the type of signal they are receiving. I'm at work now but I will check my book at home to see if I can find it there.
>
> If it's not the sync pulses in the HDSDI stream what is it that identifies the signal type? Perhaps I'm missing the obvious.
>
> --- In Avid-L2@yahoogroups.com, Bogdan Grigorescu <bogdan_grigorescu@> wrote:
> >
> > 'In the HDSDI stream the vertical broad pulses for Psf are twice the duration of those for interlace for a total of 5 and in interlace there are 10 broad pulses'
> > Any reference to backup this statement John? 
> >
> > To the best of my knowledge the fields and segments are absolutely identical, including the blanking intervals(H and V), as described in the standard: http://read.pudn.com/downloads160/ebook/723748/s274m.pdf
> >
> > BG
> > http://www.finale.tv
> >
> >
> >
> > ________________________________
> > From: johnrobmoore <bigfish@>
> > To: Avid-L2@yahoogroups.com
> > Sent: Saturday, December 7, 2013 6:16 PM
> > Subject: [Avid-L2] Re: Is it I or is it P?
> >
> >
> >
> >  
> > When you originally transcoded in the 25P project did you check how Avid had interpreted the field motion of the ama'd clips? Avid does a poor job of properly estimating the field motion. A lot of time it chooses default which isn't always correct. Job is correct that electronically i and psf are basically the same except there is temporal displacement in i media that isn't there in psf media. The difference is in how it is flagged. In the HDSDI stream the vertical broad pulses for Psf are twice the duration of those for interlace for a total of 5 and in interlace there are 10 broad pulses.
> >
> > I'm wondering if when you ama'd for the original transcode if you manually set the clips field motion to interlace if Avid would then chuck out the second Psf of the frame and double the first. In essence halving the vertical resolution. Similar to motion adapters choosing one field over both field. Worth a try just for the fun of it.
> >
> > --- In Avid-L2@yahoogroups.com, "Job ter Burg (L2B)" <Job_L2@> wrote:
> > >
> > >
> > > It makes perfect sense.
> > >
> > > If you have 50i footage and you store it as P, you are in essence folding both fields (1920x540 x2) into a single frame (1920x1080 x1).
> > >
> > > If you open that footage in a 1080i project, the field stepping command will let you step from one field to the next, where a field is nothing more and nothing less than half of the lines of any frame.
> > >
> > > Transcoding to P doesn't make it progressive.
> > >
> > > I or P, both are stored as a frame, but they are flagged differently.
> > >
> > > J
> > >
> > > On 7 dec. 2013, at 18:48, Roger <rogershuff@> wrote:
> > > >
> > > > Came a cross a weird thing (well, maybe not if someone knows the answer). I had a card full of 1080i/50 footage from a Panasonic camera. For a rough edit, I decided to transcode to DNxHD36 (P) to keep the file sizes down. I set the Project format to 1080/25P and transcoded everything I needed. I then happened to examine some of this transcoded footage in a 1080i/50 format project, at full quality. I was able to step through field by field and both fields are still there. This is a dance studio so lots of movement - and I'm not just seeing the nudging up and down of the image that you usually get with progressive footage viewed in an interlaced project. It looks just like interlaced would. Am I mad? Symphony 6.0.4 on Mac OS 10.7.5.
> > >
> >
>

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Re: [Avid-L2] Re: Is it I or is it P?

 

'If it's not the sync pulses in the HDSDI stream what is it that identifies the signal type?'
VPID - video payload identifier - SMPTE352

BG


From: johnrobmoore <bigfish@pacbell.net>
To: Avid-L2@yahoogroups.com
Sent: Saturday, December 7, 2013 8:54 PM
Subject: [Avid-L2] Re: Is it I or is it P?

 
Now that you mention it I used my waveform on the Tri-Level sync generator to view the broad pulses on a Tek 1750 a few years back. It was kind of a kludge but I could see how a true progressive Tri Level sync one set of broad pulses per frame. A Psf Tri Level was two sets of broad pulses per frame and a 1080i Tri Level was two sets of broad pulses with twice the number of broad pulses at half the duration judging by the look of things. I perhaps jumped to an incorrect conclusion that the same sync structure carried over to the sync signals in the HDSDI stream. I could not use my analogue scope to see the sync pulses of an SDI stream so I may be miss speaking. I thought I had also looked up the Vertical Sync structure in a Broadcast Engineering book too but I will have to double check.

When I was doing my tests I was trying to check that the Tri Level was locked to house black which I could see by referencing the 1750 to house black and looking for drift when set to external sync. The other thing I was looking for was how monitors know to display the various signal types they are receiving with their on screen displays and how a scope knows the difference between Psf and I. I figured the same differences I saw in the Tri Level sync must occur in the SDI stream which was what allowed the scopes and monitors to determine the type of signal they are receiving. I'm at work now but I will check my book at home to see if I can find it there.

If it's not the sync pulses in the HDSDI stream what is it that identifies the signal type? Perhaps I'm missing the obvious.

--- In Avid-L2@yahoogroups.com, Bogdan Grigorescu <bogdan_grigorescu@...> wrote:
>
> 'In the HDSDI stream the vertical broad pulses for Psf are twice the duration of those for interlace for a total of 5 and in interlace there are 10 broad pulses'
> Any reference to backup this statement John? 
>
> To the best of my knowledge the fields and segments are absolutely identical, including the blanking intervals(H and V), as described in the standard: http://read.pudn.com/downloads160/ebook/723748/s274m.pdf
>
> BG
> http://www.finale.tv
>
>
>
> ________________________________
> From: johnrobmoore <bigfish@...>
> To: Avid-L2@yahoogroups.com
> Sent: Saturday, December 7, 2013 6:16 PM
> Subject: [Avid-L2] Re: Is it I or is it P?
>
>
>
>  
> When you originally transcoded in the 25P project did you check how Avid had interpreted the field motion of the ama'd clips? Avid does a poor job of properly estimating the field motion. A lot of time it chooses default which isn't always correct. Job is correct that electronically i and psf are basically the same except there is temporal displacement in i media that isn't there in psf media. The difference is in how it is flagged. In the HDSDI stream the vertical broad pulses for Psf are twice the duration of those for interlace for a total of 5 and in interlace there are 10 broad pulses.
>
> I'm wondering if when you ama'd for the original transcode if you manually set the clips field motion to interlace if Avid would then chuck out the second Psf of the frame and double the first. In essence halving the vertical resolution. Similar to motion adapters choosing one field over both field. Worth a try just for the fun of it.
>
> --- In Avid-L2@yahoogroups.com, "Job ter Burg (L2B)" <Job_L2@> wrote:
> >
> >
> > It makes perfect sense.
> >
> > If you have 50i footage and you store it as P, you are in essence folding both fields (1920x540 x2) into a single frame (1920x1080 x1).
> >
> > If you open that footage in a 1080i project, the field stepping command will let you step from one field to the next, where a field is nothing more and nothing less than half of the lines of any frame.
> >
> > Transcoding to P doesn't make it progressive.
> >
> > I or P, both are stored as a frame, but they are flagged differently.
> >
> > J
> >
> > On 7 dec. 2013, at 18:48, Roger <rogershuff@> wrote:
> > >
> > > Came a cross a weird thing (well, maybe not if someone knows the answer). I had a card full of 1080i/50 footage from a Panasonic camera. For a rough edit, I decided to transcode to DNxHD36 (P) to keep the file sizes down. I set the Project format to 1080/25P and transcoded everything I needed. I then happened to examine some of this transcoded footage in a 1080i/50 format project, at full quality. I was able to step through field by field and both fields are still there. This is a dance studio so lots of movement - and I'm not just seeing the nudging up and down of the image that you usually get with progressive footage viewed in an interlaced project. It looks just like interlaced would. Am I mad? Symphony 6.0.4 on Mac OS 10.7.5.
> >
>



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[Avid-L2] Re: Is it I or is it P?

 

Now that you mention it I used my waveform on the Tri-Level sync generator to view the broad pulses on a Tek 1750 a few years back. It was kind of a kludge but I could see how a true progressive Tri Level sync one set of broad pulses per frame. A Psf Tri Level was two sets of broad pulses per frame and a 1080i Tri Level was two sets of broad pulses with twice the number of broad pulses at half the duration judging by the look of things. I perhaps jumped to an incorrect conclusion that the same sync structure carried over to the sync signals in the HDSDI stream. I could not use my analogue scope to see the sync pulses of an SDI stream so I may be miss speaking. I thought I had also looked up the Vertical Sync structure in a Broadcast Engineering book too but I will have to double check.

When I was doing my tests I was trying to check that the Tri Level was locked to house black which I could see by referencing the 1750 to house black and looking for drift when set to external sync. The other thing I was looking for was how monitors know to display the various signal types they are receiving with their on screen displays and how a scope knows the difference between Psf and I. I figured the same differences I saw in the Tri Level sync must occur in the SDI stream which was what allowed the scopes and monitors to determine the type of signal they are receiving. I'm at work now but I will check my book at home to see if I can find it there.

If it's not the sync pulses in the HDSDI stream what is it that identifies the signal type? Perhaps I'm missing the obvious.

--- In Avid-L2@yahoogroups.com, Bogdan Grigorescu <bogdan_grigorescu@...> wrote:
>
> 'In the HDSDI stream the vertical broad pulses for Psf are twice the duration of those for interlace for a total of 5 and in interlace there are 10 broad pulses'
> Any reference to backup this statement John? 
>
> To the best of my knowledge the fields and segments are absolutely identical, including the blanking intervals(H and V), as described in the standard: http://read.pudn.com/downloads160/ebook/723748/s274m.pdf
>
> BG
> http://www.finale.tv
>
>
>
> ________________________________
> From: johnrobmoore <bigfish@...>
> To: Avid-L2@yahoogroups.com
> Sent: Saturday, December 7, 2013 6:16 PM
> Subject: [Avid-L2] Re: Is it I or is it P?
>
>
>
>  
> When you originally transcoded in the 25P project did you check how Avid had interpreted the field motion of the ama'd clips? Avid does a poor job of properly estimating the field motion. A lot of time it chooses default which isn't always correct. Job is correct that electronically i and psf are basically the same except there is temporal displacement in i media that isn't there in psf media. The difference is in how it is flagged. In the HDSDI stream the vertical broad pulses for Psf are twice the duration of those for interlace for a total of 5 and in interlace there are 10 broad pulses.
>
> I'm wondering if when you ama'd for the original transcode if you manually set the clips field motion to interlace if Avid would then chuck out the second Psf of the frame and double the first. In essence halving the vertical resolution. Similar to motion adapters choosing one field over both field. Worth a try just for the fun of it.
>
> --- In Avid-L2@yahoogroups.com, "Job ter Burg (L2B)" <Job_L2@> wrote:
> >
> >
> > It makes perfect sense.
> >
> > If you have 50i footage and you store it as P, you are in essence folding both fields (1920x540 x2) into a single frame (1920x1080 x1).
> >
> > If you open that footage in a 1080i project, the field stepping command will let you step from one field to the next, where a field is nothing more and nothing less than half of the lines of any frame.
> >
> > Transcoding to P doesn't make it progressive.
> >
> > I or P, both are stored as a frame, but they are flagged differently.
> >
> > J
> >
> > On 7 dec. 2013, at 18:48, Roger <rogershuff@> wrote:
> > >
> > > Came a cross a weird thing (well, maybe not if someone knows the answer). I had a card full of 1080i/50 footage from a Panasonic camera. For a rough edit, I decided to transcode to DNxHD36 (P) to keep the file sizes down. I set the Project format to 1080/25P and transcoded everything I needed. I then happened to examine some of this transcoded footage in a 1080i/50 format project, at full quality. I was able to step through field by field and both fields are still there. This is a dance studio so lots of movement - and I'm not just seeing the nudging up and down of the image that you usually get with progressive footage viewed in an interlaced project. It looks just like interlaced would. Am I mad? Symphony 6.0.4 on Mac OS 10.7.5.
> >
>

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Re: [Avid-L2] Re: Is it I or is it P?

 

'In the HDSDI stream the vertical broad pulses for Psf are twice the duration of those for interlace for a total of 5 and in interlace there are 10 broad pulses'
Any reference to backup this statement John? 

To the best of my knowledge the fields and segments are absolutely identical, including the blanking intervals(H and V), as described in the standard: http://read.pudn.com/downloads160/ebook/723748/s274m.pdf

BG


From: johnrobmoore <bigfish@pacbell.net>
To: Avid-L2@yahoogroups.com
Sent: Saturday, December 7, 2013 6:16 PM
Subject: [Avid-L2] Re: Is it I or is it P?

 
When you originally transcoded in the 25P project did you check how Avid had interpreted the field motion of the ama'd clips? Avid does a poor job of properly estimating the field motion. A lot of time it chooses default which isn't always correct. Job is correct that electronically i and psf are basically the same except there is temporal displacement in i media that isn't there in psf media. The difference is in how it is flagged. In the HDSDI stream the vertical broad pulses for Psf are twice the duration of those for interlace for a total of 5 and in interlace there are 10 broad pulses.

I'm wondering if when you ama'd for the original transcode if you manually set the clips field motion to interlace if Avid would then chuck out the second Psf of the frame and double the first. In essence halving the vertical resolution. Similar to motion adapters choosing one field over both field. Worth a try just for the fun of it.

--- In Avid-L2@yahoogroups.com, "Job ter Burg (L2B)" <Job_L2@...> wrote:
>
>
> It makes perfect sense.
>
> If you have 50i footage and you store it as P, you are in essence folding both fields (1920x540 x2) into a single frame (1920x1080 x1).
>
> If you open that footage in a 1080i project, the field stepping command will let you step from one field to the next, where a field is nothing more and nothing less than half of the lines of any frame.
>
> Transcoding to P doesn't make it progressive.
>
> I or P, both are stored as a frame, but they are flagged differently.
>
> J
>
> On 7 dec. 2013, at 18:48, Roger <rogershuff@...> wrote:
> >
> > Came a cross a weird thing (well, maybe not if someone knows the answer). I had a card full of 1080i/50 footage from a Panasonic camera. For a rough edit, I decided to transcode to DNxHD36 (P) to keep the file sizes down. I set the Project format to 1080/25P and transcoded everything I needed. I then happened to examine some of this transcoded footage in a 1080i/50 format project, at full quality. I was able to step through field by field and both fields are still there. This is a dance studio so lots of movement - and I'm not just seeing the nudging up and down of the image that you usually get with progressive footage viewed in an interlaced project. It looks just like interlaced would. Am I mad? Symphony 6.0.4 on Mac OS 10.7.5.
>



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