@dirkc_be

Hi.

I think that Cyberlink Power Director will allow burning of Blu-ray disks at 50fps but you will get compatibility warnings.

Ray.

It is very strange that one can film at HD and 50 fps, but then it is impossible to burn that high quality video on BD.
Also, how come that converting 50 to 25 fps is so difficult? The tool simply could take one every two frames?
But thanks for the quick reactions both of you!

@dirkc_be

Hi.

Actually, not so strange. Don't get frame rates confused with exposure times. They are two different and separate things.

When a short exposure time is applied to less frames per second, there is larger camera movement between one frame exposure and the next frame exposure in any given pan movement, but there is less object movement captured within that frame and less motion blur if the exposure time is short. So the movement becomes much more obvious when you halve the amount of frames available (from 50 fps to 25 fps) effectively removing every other frame. The jump in movement is then exaggerated.

If you are videoing at 50 fps you can only get a maximum exposure time of 1/50s per frame whereas shooting at 25fps allows exposure times doubling that.

Doubling the amount of frames though so an image is taken at a position between the original frames and there is less of a jump in frame position between each frame during the same pan.

When shooting in very bright sunlight, exposure times per frame can be a lot shorter than the frame length regardless and you can still end up with pans that are not as smooth. This is where if possible you can manually help increase the exposure time of each frame by either reducing the aperture of your lens or if you need to keep a shallow depth of field, add an ND filter to your lens.

If on the other hand you are not dealing with camera footage then none of the above helps. So capturing screen footage is a fixed set of embedded parameters that cannot be altered. Most captured game footage that relies on variable screen frame rate refreshes can never be faithfully re-rendered if you wish to re-edit footage as video editing packages are just not designed for the job and as far as I'm aware, none at present would export the edited footage at the same variable frame rates they were captured at.

Ray.

Ray.

@dirkc_be

Go through the Burn process and choose AVCHD. In the encoder settings, you'll find a 1080P50 option. Ignore the bit about "for SD card". I'm sure there are free programs for burning the ISO (see below) to a BD (I don't do BDs so I can't suggest any at the mo). That is, of course, if MEP won't burn to your BD drive.

Practice by burning to the "Image Recorder". This will produce an ISO file, which is, in effect, a BD disk image. Double-click it to mount it in Windows as a virtual disk. To unmount it/clear it from the Windows drive tree, right-click it and choose Eject.

A test I just did with a 1080P29.97 source file gave me a 1080P50 M2TS in the BDMV>STREAM folder.

@CubeAce

Ray, I don't understand how there can be varying exposure times on a video stream without changing the framerate.

@AAProds

Hi Al.

There is no exposure time when dealing with screen captures as there is no camera sensor involved and no ISO value to control.

Just how long a frame remains on the screen varies dependent on several factors including the power of the graphics card and refresh rate of the monitor and the speed of the action of the video game as well as connection speeds to the servers. All of which can be variables. If a screen capture program is recording at a set frame rate it will only capture the frame being shown at the precise moment that frame is showing on the screen and could skip many frames between.

Ray.

@CubeAce

Ray, I see no indication that the OP is doing screen-capture.

@dirkc_be

I've just checked and IMGBURN , which I often use to burn DVDs (not much these days though) can burn Blurays. The author Imgburn gives a tute in that link for burning the actual folders, but I'd give "Write Image File To Disk" a shot.

That is, of course, if MEP won't do it.

@AAProds

Hi Al.

I agree but added the information for why some aspects of producing video are not always handled the same way and can present their own problems.

Some things I have never personally tried but could be of use for this problem is one of the plugins for camera shake to smooth out the camera movement between frames or even run it through Re-Speeder which is good at producing or taking away frames and blending frames into each other.

Ray.

@AAProds, @dirkc_be

Hi Alwyn

. . . .  choose AVCHD. In the encoder settings, you'll find a 1080P50 option . . . .

That is an option and is a progressive format removing the the progressive to interlaced issue, however a point to bear in mind is that AVCHD compression is higher (lower average bitrate) than the standard Blu-Ray h.264 with a possible loss of quality, depending on the video content. This can be seen in the example below - these are at 100% zoom.

Bitrate averages and maximum were set the same for both burns at 20 MB/s and 40 MB/s respectively

AVCHD:50 fps average bitrate 10.5 MB/s

BD 25 fps average bitrate 12.8 MB/s

As you can see a noticeable difference.

HTH

John EB

Thanks a lot for all that information guys! It still surpises me that blue-ray disks don't support - by default - the 1080i 50fps video's. The work-arounds can be usefull, but are - only - work-arounds...
When I export the video as mp4, in HD and 50 fps, then every PC can play it without any problem. Also, I've published the video on Youtube, and yes the quality is HD (framerate not known). But on a BD I can't burn it directly. Strange!

@dirkc_be

. . . . don't support - by default - the 1080i 50fps video's. . . . .

The interlaced format and frame rates are 'left overs' from when the old CRT TV's and monitors which supported frame rates of 25 fps (PAL) and 29.97 fps (NTSC) were in use.

To all intents and purposes Interlaced video is an obsolete format.

Modern TV broadcasts are digital with TV's and monitors being progressive devices and having 'framerates' from 50/60 fps up to 200 fps depending on the make/model .

. . . . . . . . When I export the video as mp4, in HD and 50 fps. . . .

There are several 'gotchas' in terminology used, such as 'fps' when referring to interlaced video, 'mp4' and HD which can cause misunderstandings.

Interlaced video: by convention when you quote a video as 1080i the 'f' in 'fps' means Fields, not frames, so a 1080i 50 fps is 50 fields per second which equates to 25 frames per second, one frame is comprised of 2 fields as explained in this article

MP4 is a file container format not a video standard. Depending on the video codecs used within the mp4 file, not all are playable on a computer or other device without the required decoder (codec) being installed - the most common example is some of the Quicktime formats inside an mp4 file format.

If you are selecting an mp4 export preset in the program, by default the video is encoded as h.264 format with the audio AAC format - these are the most universal playable format.

HD is often used incorrectly to refer to 1080p or 1080i resolution video as well as the 720p format. 1080 is FullHD

. . . . I've published the video on Youtube . . . .

Youtube and other similar sites such as Vimeo, re-encode the video you upload at the resolution you upload and down to aa low a resolution such as 240p and is always progressive. This is to cater for the wide range of Internet connection speeds to ensure as smooth as possible playback.

HTH

John EB

@dirkc_be

I've published the video on Youtube, and yes the quality is HD (framerate not known)

Dirk, right-click on the video in the You Tube player and choose "Stats for Nerds". That will tell you the framerate.

When I export the video as mp4, in HD and 50 fps, then every PC can play it without any problem. Also, I've published the video on Youtube, and yes the quality is HD (framerate not known). But on a BD I can't burn it directly. Strange!

What your source video is has no bearing on the export format and whether it will play in something. That is entirely up to the encoder, in this case MEP. The fact that MEP won't produce a 1080P50 BD is entirely a decision made by Magix, for whatever reason.

@johnebaker

John, I don't think your comparison is valid. 50P is twice the number of frames as 25P and therefore requires twice the data. Comparing the two with the same bitrate (or in your case lower bitrate for 50P) I think is not going to produce a valid result. Since Magix doesn't have a CRF export, one can only double the export bitrate to give a fair comparison.

@AAProds

Hi

. . . . John, I don't think your comparison is valid. 50P is twice the number of frames as 25P and therefore requires twice the data. Comparing the two with the same bitrate (or in your case lower bitrate for 50P) I think is not going to produce a valid result. . . . .

In principle I would agree with what you are saying, however getting a smaller file size for double the framerate shows how much more compression there is.

As I said in my comparison, both formats were set for the same target average and maximum bitrates in the advanced settings of the burn dialog, and the same GOP length (I forgot to mention this), and the yet the AVCHD file was still smaller and lower average bitrate.

John EB

@johnebaker

The only way to do a valid comparison would be to export at double the bitrate for the 50fps export. And we're only talking about AVCHD because that was the format of the 50P preset I found. Perhaps, because it is "for and SD card", the encoding quality is different. That is probably the reason for the 25% lower bitrate. It is illogical that two exports of the same source into the same codec at the same bitrate would come out with different file sizes bitrates. That's what the "average bitrate" setting is for.

Could you redo your lizard test with double the bitrate for the 50P version?

@AAProds

Hi Alwyn

. . . . Could you redo your lizard test with double the bitrate for the 50P version? . . . .

Not sure what that would achieve as the encoder decides the actual average bitrate based on the 'motion' in the scenes.

I repeated the test with setting the average bitrate target to 38 Mb/s (38000 Kb/s) and the result was similar to the previous test - average bitrate of 10.8 Mb/s, and no visual improvement of the lizard.

Out of interest I also exported as video files AVCHD and MP4 h.264 with average and max bitrate , CBP, GOP length, profile, quality setting as before and 50 fps and got the following:

AVCHD - ave bitrate 8.2 Mb/s

MP4, h.264 ave bitrate 7.4 Mb/s - the file size is approx 12% bigger than the AVCHD

Looks like the hidden export parameters (quality) for the encoder could be different for BD compared to the export options. AFAIK the quality slider affects the hidden parameters - the question is how!

John EB

The interlaced format and frame rates are 'left overs' from when the old CRT TV's and monitors which supported frame rates of 25 fps (PAL) and 29.97 fps (NTSC) were in use.

To all intents and purposes Interlaced video is an obsolete format

I don't know about the US but in this corner of the planet Freeview TV transmissions are 1080i ( PAL HD) and 576i (PAL SD). Checking the UK shows this to also be the situation there. So interlaced TV is still around.

@ericlnz

Hi Eric.

The last analog TV transmitter was switched off in Northern Ireland in 2012. All UK television transmission is now digital.

Ray.

John, I don't think your comparison is valid. 50P is twice the number of frames as 25P and therefore requires twice the data

But remember bitrate is measured as bits per second. The image size and number of frames per second don't come into it.

The same bitrate used to export 25p andf 50p should give identical file sizes if using CBR. If using VBR there may be slight variation.

@ericlnz

Hi Eric.

The last analog TV transmitter was switched off in Northern Ireland in 2012. All UK television transmission is now digital.

Ray.

Yes it may be digital but it's still interlaced. https://www.tvchannellists.com/w/List_of_channels_on_Freeview_(United_Kingdom)

@ericlnz

Huh! Well I continue to learn something every day 👍😂

Thanks.

Ray.

@ericlnz

But remember bitrate is measured as bits per second. The image size and number of frames per second don't come into it.

That wasn't my point. My point was that that same bitrate is now spread over double the number of frames, which would logically mean that the quality of each frame would be lower.

@johnebaker

I did a test encode of 50i verses 50P with Virtual Dub and X264, CRF of 18. The 50P file was 30% larger than the 50i file. I deduce from that that the Magix h.264 BD encoder settings and the AVCHD h.264 settings are different, somehow, and therefore cannot be compared.

It would be interesting for @dirkc_be to create an AVCHD BD ISO using the 1080P50 preset and see if the movement is smoother.

Yes it may be digital but it's still interlaced.

Same in Oz: HD TV is AVC, 1920x1080 25fps Interlaced Top Field First.

@ericlnz

Hi Eric

. . . . .But remember bitrate is measured as bits per second. . . . .

That is correct however,

. . . . The image size and number of frames per second don't come into it. . . . The same bitrate used to export 25p andf 50p should give identical file sizes if using CBR . . . .

I do not see how they cannot, and don't, respectively.

For example h.264 1080p video at 25 fps and a CBR of 20Mb/s each frame would get 0.8 Mb per frame for the data, at 50 fps each frame would get 0.4 Mb and yet both are 20 Mb/s, and as has been commented on many times in the forum CBR can make the video look worse as frames that need more data do not get it.

The same goes for resolution - 2160p requires a higher bitrate per second then 1080p for the same frame rate - there are 4x as many pixels to store data.

. . . . this corner of the planet Freeview TV transmissions are 1080i ( PAL HD) and 576i (PAL SD) . . . .

True, interlaced video is a 'leftover' from the early days of CRT TV's and Monitors and is still used for digital transmissions as it requires less bandwidth.

Modern TV's and monitors are Progressive devices, however letting the modern TV de-interlace video is a far better option than doing it in a video editor or watching interlaced video on a computer - the de-interlace filters are far superior.

John EB