1080p@50fps transition blocks

[RuneW]

Hi,

I'm trying out a trial version of VS X5 before deciding whether to buy it or not.

Before buying I want to make the simplest of projects in 1080p@50fps. But right from the start it seems
like this is not going to be easy...

I don't know if this is related to the "transition end blips" bug, but somewhere in the transition (probably at the end?)
I get these nasty blocks:

I have tried a few players and all shows the same blocks. But to be sure: Could you try to playback the video file
and see if you get the same blocking?

I have put it here (it's ca 20MB):
http://www.sub20hz.com/data/transition_test.m2t


If it's the "transition end blips" bug, which Corel hasn't been able to fix since X2, then I cannot go for X5 as my video editor.
A shame since it was otherwise relatively stable and easy to use. I'm starting to suspect that there are no sub 100$ video editor
that is usable, even for simple 1080p@50 projects...

[skier-hughes]

tried it here exactly the same result.
Have you tried re-encoding it and checking what the results are?
Encoding using different settings?
They are compression blockiness, which may come from the transition encoding.
Can you upload the two videos in raw state, so I can put the two pieces into VS and other software and encode it myself?
What settings did you choose to encode?

[Ken Berry]

Can we assume you ticked the box beside 'Enable 60P/50P editing' under Settings? And like Graham, I would like to know how exactly you produced that clip? Share > Create Video File > Same As First Clip or by choosing a specific (custom?) output?

I have looked at your clip and confess I simply cannot see any pixelation at all during the transition on my 24 inch 1920 x 1080 full HD monitor. Certainly not on the X5 preview screen -- but then again I probably would not have expected to. But I also checked it in VLC Player playing it full screen several times and pausing at the transition. All I could see were the transparent outlines of rocks through the girl's arm. But definitely no pixelation.

Curiously enough, though, I also tried playing it in Windows Media Player, three times. And each time it crashed precisely at the transition. No message with any useful information apart from "WMP has stopped working and will close". But obviously it did not like something about the video at the transition point.

[RuneW]

tried it here exactly the same result.
Have you tried re-encoding it and checking what the results are?
Encoding using different settings?
They are compression blockiness, which may come from the transition encoding.
Can you upload the two videos in raw state, so I can put the two pieces into VS and other software and encode it myself?
What settings did you choose to encode?

The project is gone, but I'm pretty sure I used these settings:

(the video rate may have been 12000)

The raw videos directly from my Sony Alpha 65 can be found here:

http://www.sub20hz.com/data/Transitionblocks/00001.MTS
http://www.sub20hz.com/data/Transitionblocks/00009.MTS

[RuneW]

Can we assume you ticked the box beside 'Enable 60P/50P editing' under Settings? And like Graham, I would like to know how exactly you produced that clip? Share > Create Video File > Same As First Clip or by choosing a specific (custom?) output?

No, actually The "Enable 60P/50P editing" setting was not checked. What on earth does that setting mean? Must it be checked to be able to edit 50P videos or something? Seems strange to have to enable something like that specifically.

I did not use same as first clip, but custom.

I have looked at your clip and confess I simply cannot see any pixelation at all during the transition on my 24 inch 1920 x 1080 full HD monitor. Certainly not on the X5 preview screen -- but then again I probably would not have expected to. But I also checked it in VLC Player playing it full screen several times and pausing at the transition. All I could see were the transparent outlines of rocks through the girl's arm. But definitely no pixelation.

Curiously enough, though, I also tried playing it in Windows Media Player, three times. And each time it crashed precisely at the transition. No message with any useful information apart from "WMP has stopped working and will close". But obviously it did not like something about the video at the transition point.

Hmmm.... I've just been trying with a third player (XBMC) and in that player I didn't see the blocks either...

[Ken Berry]

No, actually The "Enable 60P/50P editing" setting was not checked. What on earth does that setting mean? Must it be checked to be able to edit 50P videos or something? Seems strange to have to enable something like that specifically.

In a sense, it is a sort of interim response by Corel to the advent of camcorders which film at 50/60 fps. X4 did not have the capacity and you had to use a very round about method of dealing with the then new format. X5 improved things a bit by enabling editing of such video and producing video with the same frame rate, albeit with a lower maximum bitrate (18 Mbps) than the bitrate of camcorders which can film at that frame rate (max. 28 Mbps). Clicking that button will then change the Project Properties to include that frame rate, albeit in .avi rather than mpeg format. But at least the frame rate is there...

This is a little off the topic, but I notice that your original video uses a frame rate max. of 25,999 bps -- which is a good deal higher than the max you can achieve with X5. If you want to produce video with exactly the same properties as your original, here's how. Go to Settings > Make Movie Template Manager and select it. On the dialogue box which appears, click the Add button at the bottom. A new dialogue box will appear. The top window just has a button with "..." on it for the Path. Click that button and navigate to where you have one of your 50P video clips and select it. The full path to it should now appear in that top File Path window. Give the template a meaningful name e.g. 50P_AVCHD, and click OK to close the dialogue box. Next time you want to make a video with those properties, choose Share > Create Video File, and your template will appear at the very bottom of the drop down menu.

[RuneW]

This is a little off the topic, but I notice that your original video uses a frame rate max. of 25,999 bps

I'm a little confused. Do you man data rate of 25 999 000 bps or frame rate of 25,000 fps?

If you want to produce video with exactly the same properties as your original, here's how.

I guess the data rate is not that important, but the framerate certainly is. Thanks for the tip anyway!

[Ken Berry]

The data rate (or bitrate) is HIGHLY important to quality. The higher the bitrate, the higher the quality. The frame rate, on the other hand, is more or less fixed -- 25 frames per second (interleaved) or 50 full frames per second when the video is high def and progressive. The latter frame rate gives better quality than 25 fps, but the bitrate is still the main thing which fixes the end quality (apart from the skills of the cinematographer, of course!)

So making a template with the method I outlined, will produce video with the same bitrate -- and thus quality -- of your original. Using the VS default maximum bitrate of 18 Mbps will produce video of slightly less quality than your original 26 Mbps.

[RuneW]

The data rate (or bitrate) is HIGHLY important to quality. The higher the bitrate, the higher the quality.

Ofcourse!

I expressed myself a little clumsily. What I meant to say was it's much less important to me that the bitrate is IDENTICAL to the original bitrate than the framerate being identical (not halved)

[skier-hughes]

changing the bitrate is not something you want to do unless you need to.
Changes made to the video lead to recoding, this will lead to quality loss.
You cannot increase the quality of an 18Mbps video by saving it as a 26Mbps video, the recoding completed on the saving will lead to a very slight degradation.

So, wherever possible retain all the same settings until the very final part, the making of a dvd or bluray disc, saving for YouTube etc.

[erdna]

RuneW: no issues on playback with PowerDVD, VLC Player, Splash Lite, Media Player Classic. Only WMP on W7 looks shaky (no lockup). My experience for quite some time is that WMP is the worst player for 1080p50 material.
Bitrate: even at the same bitrate there is no garantee for keeping the same quality. If the footage is recoded, there are more parameters involved (Q-table,GOP option...) than just the bitrate budget (different codec flavors). Onlt with smart render, the quality remains the same for non processed parts.

[Kingston]

I don't see any blockiness, either. I believe what you are seeing are the rocks from the previous scene fading out.

In the Video Save Options window, if you clear the checkmark next to AVCHD, you can then bump the bitrate to 20 000. The only reason I can determine for the check next to AVCHD is to limit the bitrate to 18 000, which is the legal limit for AVCHD on DVD.

[RuneW]

I don't see any blockiness, either. I believe what you are seeing are the rocks from the previous scene fading out.

Suspiciously rectangular rocks then, wouldn't you say?

(This is the screendump of the actual playback (the same as I provided in the first post in this thread))

But it's seems this was a problem with VLC and not the encoding as such (I hope), so it's not really an issue anymore.

Well, actually the only player that seems to playback my 50fps content is XBMC, so for each time I have made a clip I have for fire up XBMC the check it out. Cumbersome, but it works. My PC probably needs a clean install of Windows in the near future..

[Ken Berry]

I never thought you *weren't* seeing those blocky pixels -- it's just that I and others were not seeing them. But I guess the real test is to play back the converted video on a HDTV to see how your converted video looks.

[RuneW]

I never thought you *weren't* seeing those blocky pixels -- it's just that I and others were not seeing them.

The very first replier wrote that he in fact did see the exact same thing - so I'm obviously not the only one:

tried it here exactly the same result.