Hi Peter,
I think if you set preview in Vegas to Best / Full and disable scaling you'll see the flicker there as well. Vegas does discard a lot of what's in every frame of video, never trust its preview when looking for a problem without being in Best / Full and disabling scaling. Other players don't do what Vegas does so you get to see the problem(s).

Bob.

Hi Bob, thanks for responding.

In Options/Preferences/Preview Device I unchecked "Scale output to fit display" and still Vegas played without any flicker at all, whether the preview was top right hand corner or full screen.

Kit - sorry if I confused. I meant that on the same computer, same monitor, with exactly the same clip, there is flickering in WMPlayer, VLC Player or Internet playback, but Vegas and DVDA play it without flicker.

Given that three players say there's something wrong with it I think it's safe to assume something [I]is[/I] wrong with it. The question then is how come Vegas shows it as OK?

Some more details might help, like how and as what was it rendered out of Vegas?

Also, just to be sure, to be sure, you have turned Off the "Automatically Adjust Playback quality..." thingie so Vegas is forced to display every frame, field and line?

Bob.

Thanks Bob,

Firstly, it's not just this clip, it's absolutely ANY video on this particular computer. I used this one as an example because it is also on Youtube.

This self same clip, and any other clip, plays fine on any other computer in WMPlayer, VLC Player or the Internet, so it seems to be something on just the one computer.

Setting wise, I do not have "Adjust Size and Quality for Optimal Playback" enabled.

I agree with you - the question indeed is how come Vegas (and DVDA) plays it OK?

The demo video that you posted had the following characteristics:

Video
ID : 2
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L4.0
Format settings, CABAC : Yes
Format settings, ReFrames : 3 frames
Format settings, GOP : M=4, N=15
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 1mn 38s
Bit rate mode : Variable
Bit rate : 14.0 Mbps
Maximum bit rate : 24.0 Mbps
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 25.000 fps
Standard : NTSC
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.271
Stream size : 165 MiB (99%)
Language : English
Encoded date : UTC 2014-12-11 03:07:26
Tagged date : UTC 2014-12-11 03:07:26

I dropped it on the Vegas Pro 13 timeline and observed a blue frame about every 23 or 24 frames. What's up with that?

Absolute Frames:
1246-1223=23
1223-1200=23
1200-1176=24
1176-1153=23
1153-1130=23
1130-1106=24
1106-1083=23
1083-1060=23
1060-1036=24
1036-1013=23
1013 - 990=23
_990 - 966=24

There's a pattern here.

Very interesting observation John, thank you.

The blue frames I think only appear on the "flickering" portions of the clip, i.e. The VLC Player and the Youtube footage - in other words it is in fact these blue frames that are causing the flickering!

They are definitely not in the original clip that is being played, and I must stress that this issue has nothing to do with any particular clip - it happens on this computer with absolutely ANY video clip, whether played from my Hard Drives or from the Internet, except as I said if I play them in Vegas or DVDA.

The clip I put on Dropbox was created by shooting the computer screen with my EX1, as I used the various methods of playing the original clip, then rendered to MP4 using a Main Concept template.

So, what is happening is that somehow this computer, except in Vegas and DVDA, is, during playback, displaying a blue frame every 23 or 24 frames.

All I need to do now is find out how or why and correct it!

Thanks for your interest.

Peter

I'd be a smidge careful making any conclusions based on taking a video of a computer screen. Many computer screen's refresh rate isn't PAL compatible so I'd expect some weirdness.

Bob.

Yes Bob, and this incompatibility did cause a certain "waviness" in the frame which I commented on in the clip I posted.

But, the flickering which the camera recorded is also very visible to the naked eye - that's what the original problem was/is. John Dennis took the trouble to analyse and identified these blue frames, which I then also found.

Interestingly I just viewed a few other clips on Youtube (including Rory's Flat Earth ! ) and with these the flickering was not blue but yellow.

If you say the clip play fine on other PCs then I'm wondering if the problem is the codecs installed on the PC with the problem.

Bob.

.. just got in. That's an interesting area to check Bob.

- what about the Internet - does Youtube have recommended codecs?

First of all, when Bob suggested that you set your Vegas preview to "Best / Full," you responded that you changed the video scaling, but that is NOT what he was asking about, and it will not cause Vegas to show the problem. You must change the Vegas preview quality, which is changed using the icon at the top of the preview display itself. If it is set to anything other than Best/Full, Vegas will cover up all sorts of nasty stuff in order to make the video play more smoothly.

As to the problem itself, I too noticed a more-or-less regular pattern. It is definitely not a flicker, because that word is normally used for luma or chroma intensity changes, not for completely corrupted frames. Also, flicker is usually used to describe levels changes that happen several times a second, whereas this only happens about once per second.

Semantics aside, the nature of this problem strongly suggests that something is non-standard with the GOP setting used during encoding. What codec was used to create the video? What program did the encoding (Vegas? MeGui?) ? Were any changes made to the default codec parameters?

Another possibility is that this video was cut or manipulated by some program subsequent to its original encoding. I have seen VideoRedo totally screw up certain types of AVC files, although more recent releases seem to do a better job. However, if you play around with the Options in VideoRedo, you can seriously screw up your video (I know this because, with the help of their support team, I managed to do exactly that -- they eventually helped me out of the mess they got me into). Other programs that cut AVC/MP4 video can also do damage.

Thanks John,

Sorry I omitted to mention it above, but I already had Vegas set to Best/Full.

I used the word flicker as a general description - as we now know it is in fact a coloured frame every 23 or 24 frames.

The important thing however is that this has nothing to do with the encoding of any particular video clip.

This computer displays the coloured frame for ANY video clip, except in Vegas or DVDA.

The coloured frame is not actually in the video clip, it is a playback display aberration.

It has not affected the output of any work I have done in Vegas, only if I playback a clip outside Vegas or DVDA on this particular computer.

If I play ANYTHING on Youtube on this computer, it does it.

If I play a BBC produced DVD on this computer, it does it.

It has always done this. Because I use the computer almost exclusively for Vegas and Vegas does not do it, it took me almost a year to find the problem. The shop I bought it from will take a look if I leave the PC with them for a week, but I am currently too busy using it so I am trying to solve it myself.

If I have no joy I shall wait till I am not so busy in the new year and take it back to the shop, but I was hoping that a fellow Vegas user may have come across something similar.

This computer displays the coloured frame for Well that is a totally different story. I thought it was a problem with a specific clip.

I think that Vegas still uses the very outdated "video for windows" architecture, and is about the only thing left that does. Most other apps use (I think) DirectShow. These are video architectures inside Windows itself.

Someone else with more knowledge about this will have to chime in (although almost no one is left in these forums, so you may not get a reply). If, however, what I say is correct, then your more complete description of the problem makes me think that something in your DirectShow setup got screwed up, and will require some sort of re-installation. I am not quite sure what to point you to, but I think I am on the right track.