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chrisvids  
#1 Posted : Saturday, August 10, 2019 12:25:50 AM(UTC)
chrisvids

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Austria

Hello!
I'm relatively new to vMix and I'm trying out whether it is an appropriate alternative to Qlab or PlaybackPro on a Windows machine.

Now I tested out a few files and had to realize that some looked way worse than played back via VLC.

My test clip here is a ProRes 422 in 1080i50. Are there settings to change the deinterlacing in vMix? I only found in the "decoder" setup none/blend/discard where no option delivers a good result, so I sticked to blend. In the clip settings it says under "deinterlacing" "Bob UpperFieldFirst". Is there a way to change this setting, it seems like I can't change anything?

Here is a screenshot from playback in vMix:
screenshot_vmic.jpg (1,033kb) downloaded 10 time(s).

and here approximately the same clip position played back in VLC:
screenshot_vlc.jpg (1,097kb) downloaded 11 time(s).

You notice - especially in the subtitles which are burned in the file - how much smoother the image in VLC looks. Also when played back with vMix the subtitles are a bit jittery. I thought it might be a deinterlacing issue with wrong fields but maybe there is something else that I'm missing. Also you see the differences in contrast.

Are there any suggestions what I could do to improve image quality?
In this special case and general recommendations for best settings when focus is playback quality (without live capturing I don't care so much about latency, as the sound tech can adapt the audio delay.
In the "performance" settings of vMix I chose the default graphics adapter which is my GeForce GTX 1070 and enabled "high output performance mode" and chose "smooth" as a display method. vMix is set to 1080p50 which will be my output resolution.

My main focus is on playing back videos on a second output in the best possible quality, at the moment I don't need streaming and capturing. If it works fine I'll use it at a festival next week.
At this festival I will need to play back videos of different formats and need one solid machine to playback them all, there is no time for rendering all files in the same codec. It usually is mainly .mov with ProRes 422, 422HQ, 4444 and .mp4 or .mov with h.264. Framrates mostly 24p, 25p, 50p and 50i, resolutions between 720p and 2K.

If you need more informations about my setup just ask. Any help is highly appreciated.

Thanks in advance,
c
admin  
#2 Posted : Sunday, August 11, 2019 7:15:03 PM(UTC)
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Hi Chris,

A few things to note:

1. The black level in the VLC screenshot appears to be incorrect as the blackest level is 16, while the lowest level a monitor can display is 0.
vMix automatically adapts to show the correct black level while VLC does not on some graphics cards, so that explains the difference there.

2. The resolution will depend on the deinterlacing used, what deinterlacing method are you using in VLC for comparison?
By default it is set to none in VLC, so if you aren't seeing interlaced lines in VLC it means the source footage is actually 25p
and it is recommended you re-encode to 25p.

3. For the highest resolution when playing to a progressive display, set the output frame rate to 25p.
This will convert 50i to 25p through blend deinterlacing.
Conversely, if you would like the highest possible smoothness set the output to 50p.
This will reduce the quality as each field is separated into a frame and upscaled. This is likely what you are seeing on the text at the moment.

Finally, if you plan on outputting progressive video only, then it is recommended to re-encode the videos to progressive as well ahead
of time to ensure the highest possible quality.

Hope this helps.

Regards,

Martin
vMix
thanks 1 user thanked admin for this useful post.
sinc747 on 8/12/2019(UTC)
chrisvids  
#3 Posted : Tuesday, August 13, 2019 4:44:34 PM(UTC)
chrisvids

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Austria

Thanks for the clarification,
it makes sense for the black level. For the Deinterlacing I was pretty sure that I tested setting it to none in vMix before but I tried it again and now it works and it looks as sharp as with vlc, so maybe it was a user error.

Yesterday we built our setup, it is for a short film festival, and tested the footage, now I'm having some more questions.

- Is there an easy way to change aspect ratio with settings like fit/fill/stretch? With most clips the ratio seems to work fine or I have to change between widescreen and source. However there is for example one film that has a resolution of 1998x1080, so it is slightly wider than 1080p. So when playing back in a 1080p-project I suppose I should get small letterboxing on top and bottom, but there is none and it seems like it crops some pixels on the left and on the right. Is there a solution to make sure that no clips are cropped?

- Is there a solution to set in- and out-points of videos? I found the playlist feature where you can set start point and duration, however it is only in seconds and I don't need a playlist, I only need single clips.
-- edit: Found the solution, I was searching the manual for in- and out-points instead of start- and end-points =)


- When playing a clip, is there a way to stop playback and clear program? At the moment I switch to a black solid, but maybe there is some other way?

- Can I play subtitle-files with a clip, I got some in .srt?

Many thanks,
c
chrisvids  
#4 Posted : Wednesday, August 14, 2019 8:52:52 PM(UTC)
chrisvids

Rank: Newbie

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Joined: 8/9/2019(UTC)
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Austria

Sorry for spamming, one more newby question:

- When playing back video files by default vMix is set to hold the last frame of the video. Is there a setting to change this behaviour (and change the default settings, so I don't have to change the triggers for every clip by hand)? I'd like to have it just stop and have a black screen, so either it cuts (to my black solid which is in preview) or just kills the video after it finished playing.

Thanks,
c
ask  
#5 Posted : Thursday, August 15, 2019 6:30:13 AM(UTC)
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Read up on using Triggers in the Help files.....
chrisvids  
#6 Posted : Thursday, August 15, 2019 11:28:40 AM(UTC)
chrisvids

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Thanks for the hint, maybe I don't understand it completely but it seems to me that triggers do not change the default behavior of clips, but are programmed for a single clip. My point is if I get 10 clips for a sessions where maybe 1 or 2 don't end with a black frame I don't want the last frame to freeze when playback ends. So it would be nice to know how to change the setting for all clips that are imported into vMix. Is this possible with triggers?

This and the aspect-ratio-question are the two most important topics for me at the moment.
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#7 Posted : Thursday, August 15, 2019 6:46:10 PM(UTC)
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Also look for the LIST and PLAYLIST functions. PLAYLIST allows you to specify the length of each item and the transition behaviour.
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