How to record a synchronized video while switching from 50Hz to 60Hz

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By tfh

Paragon (1484)

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29-10-2017, 14:10

I finally got arround to do something I wanted to do for quite some time: Make some decent videos of some Fony stuff. Using the -doublesize feature from OpenMSX and then converting them to mp4 worked very very well for The Yellow Alert Demo, the Fony DemoDisk #2 Promo and Fony DemoDisk #2, but... I ran into trouble with Fony DemoDisk #1.
It seems that we have switched from 50Hz to 60Hz a few times during this demo, and as the OpenMSX documentation mentiones: This can give synchronisation problems between the video & Audio. And indeed it does :)
Is there something I can do within OpenMSX (Force 60Hz) or is there any workaround I can use?

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By Meits

Scribe (4525)

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29-10-2017, 15:00

I ran into this a few times as well. My solution for the sake of the video was to record it in both frequencies and concatenate the clips.
Now I'd choose to let open broadcast studio record the window in which openMSX is running. Never tried this, but i guess it'll work.
I do hope a sollution will appear some time in the future.

By NYYRIKKI

Enlighted (4743)

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29-10-2017, 15:00

openMSX Console Command Reference wrote:

Use record_chunks_on_framerate_changes if you want to split up the recording in several files, whenever the frame rate of the MSX changes. An AVI file cannot contain video of multiple frame rates, so sound and video will get out of sync if that happens without using this special version of the command. Do not specify the target filename with this variant, or openMSX will record all chunks to the same file.

By tfh

Paragon (1484)

tfh's picture

29-10-2017, 15:49

@Meits: OBS seems to be a good solution. I will go and play with it Smile Now I need to find out how to keep the OSD [LED's] away :-)
@NYYRIKKI: Thanks Smile But I am indeed aware of that, but I want the make one clip of that demo, so ending up with multiple files is not the solution in this case Smile

By tfh

Paragon (1484)

tfh's picture

29-10-2017, 16:06

Hmmm, OpenMSX might not be the right choice anyway. It seems it doesn't like how the screensplit was implemented in the last part. (This also went wrong with FDD #2).
I have no clue if it's an OpenMSX bug or just bad programming on our side Smile

By yzi

Champion (409)

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29-10-2017, 16:34

How about 300 fps? Smile In 50 Hz modes it would do exactly 6 video frames for every emulated frame, and in 60 Hz modes exactly 5 video frames for every emulated frame.

By Grauw

Enlighted (6255)

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29-10-2017, 17:30

I think the idea is that you can use external video editing software to combine the separate clips.

By NYYRIKKI

Enlighted (4743)

NYYRIKKI's picture

29-10-2017, 17:31

yzi wrote:

How about 300 fps? Smile

I could not help my self from thinking exactly as you did. Smile How ever maybe more realistic approach would be changing the AVI-format to some other container format that supports VFR (Such as Matroska or similar)

By tfh

Paragon (1484)

tfh's picture

29-10-2017, 18:25

Grauw wrote:

I think the idea is that you can use external video editing software to combine the separate clips.

That would indeed be an option, but that would be more or less a last resort: I've never used video editing software, so I would need to spend time on selecting a decent freeware program and learning how it works.
But, as it seems that OpenMSX doesn't run the last part of FDD #2 correct, I need to look for another solution anyway.

I also wonder where I got the FDD #1 I currently use (probably ripped it from Youtube) and what emulator was used to record it.

NYYRIKKI wrote:
yzi wrote:

How about 300 fps? Smile

I could not help my self from thinking exactly as you did. Smile How ever maybe more realistic approach would be changing the AVI-format to some other container format that supports VFR (Such as Matroska or similar)

That would indeed be very nice. Most recent CPU's even support hardware encoding to h264, so you will only add a little CPU load.

By tfh

Paragon (1484)

tfh's picture

29-10-2017, 20:45

OK, BlueMSX seems to work, but I can't get 1:1 pixelmapping with it, as it automaticly records to 640:480.
But, it's the best I can do right now, so I'll update that one when the F1 race is over...

By Manuel

Ascended (13469)

Manuel's picture

29-10-2017, 23:27

What exactly is going wrong? Are you talking about the end-part with the credits? That looks pretty normal to me...

Also, I once recorded FDD2 (see my YouTube video), is something wrong in that video's last part too then, as you suggest?

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