What's the best way to change a video (.mkv) resolution?

[MC23]

Hello everyone, I have a problem with a video: its current resolution is 1980x1080p, but originally the video is 1920x886 (EDIT: wrong! I meant 816), so when I open it with VLC, no matter if I put it fullscreen or not, but black bands will appear on top and bottom of the video: I'd like to maintain every setting of the video (bitrate, fps, video codec etc) and only change the resolution: I've read it's not possible to do this without re-encoding but I didn't understand how to do it by re-encoding it maintaining the same settings of the original video except for the resolution... I hope I have explained myself...

Here are the screenshots of the original video and the modified one: https://imgur.com/a/x1YKL3H

[MC23]

Yes, when it's not played in FS the 886 is shown correctly, but the 1080 one keep the bands (it's like the 886 video was screen captured in fullscreen mode). I'll try that software and let you know if it helps

[jagabo]

The image you posted was 1920x816. That's 2.35:1 -- one of the most common widescreen movie aspect ratios. So your movie is probably playing exactly the way it should on a 16:9 monitor. Almost nothing outside of made-for-TV content is 16:9. Learn to live with it.

https://en.wikipedia.org/wiki/Aspect_ratio_(image)#2.35:1_and_2.39:1

Check your movies aspect ratio at imdb.com. I'm sure you'll see it's 2.35:1.

[MC23]

The image you posted was 1920x816. That's 2.35:1 -- one of the most common widescreen movie aspect ratios. So your movie is probably playing exactly the way it should on a 16:9 monitor. Almost nothing outside of made-for-TV content is 16:9. Learn to live with it.

https://en.wikipedia.org/wiki/Aspect_ratio_(image)#2.35:1_and_2.39:1

Check your movies aspect ratio at imdb.com. I'm sure you'll see it's 2.35:1.

I don't think you understood: I have two versions: one is 1920x886 (the one on top on the link I posted) the other one is 1920x1080: the second one has 265 codification but it has black bands even if I don't play it in fullscreen: I'd like to cut it to 1920x886 trying to maintain good quality.

[hello_hello]

As jagabo said, the first image you posted is 1920x816. There's a chance the encoded resolution was 1920x886 and the player is squishing the height to 816 on playback, but I don't know why anyone would encode it that way. Do you mean 1920x816 and not 886?

For the second video, the only way to remove the black bars is to re-encode it. The screenshots aren't the same frame, but if they're any indication the first one is better quality anyway.

When re-encoding, it's somewhat pointless using the same encoder settings, or trying to, because the video is decompressed and sent to the encoder. You'd use the desired settings for the new encoder because it's oblivious as to whether the video has been encoded before. It just sees the raw, decompressed video. It's a bit like decoding an MP3 as a wave file (decompressed version), and then re-encoding the wave file as an MP3 again. The mp3 encoder just sees the wave file and is oblivious to how it was encoded originally. The higher the bitrate you use for the new MP3, the more it'll sound like the wave file. If the original Mp3 used a low bitrate and doesn't sound great, using the same bitrate again will make it sound worse. Video encoders are like lossy audio encoders in that respect. They throw information away. Encoding can also introduce artefacts, especially if a low bitrate is used, so when you re-encode again, the second encoder has to effectively encode the video plus any artefacts introduced by the first encoder, requiring a greater bitrate for the same quality than if it was encoding the original video for the first time.

You'd keep the frame rate, remove the black bars, and you can use the same encoder again if you want to, but you'd want to use the settings and an appropriate bitrate for the encoder to reproduce the video at a visually similar or equal quality, which doesn't necessarily mean using the same settings (or even the same encoder) as before.

Maybe try Vidcoder or Handbrake. You can crop the black bars and encode at a decent quality using the x264 encoder (you haven't even specified what the original encoder or codec was). x264 is the most commonly used encoder for that sort of thing these days. Those programs are fairly simple to use, but post back if you need help with them. I don't use them myself, but others here do.

Do you actually watch the video any other way than fullscreen? If you don't, then unless you have a display with an aspect ratio other than 16:9 (1920x18080 etc) there's probably not much point to re-encoding solely for the purpose of removing the black bars.

[MC23]

As jagabo said, the first image you posted is 1920x816. There's a chance the encoded resolution was 1920x886 and the player is squishing the height to 816 on playback, but I don't know why anyone would encode it that way. Do you mean 1920x816 and not 886?

For the second video, the only way to remove the black bars is to re-encode it. The screenshots aren't the same frame, but if they're any indication the first one is better quality anyway.

When re-encoding, it's somewhat pointless using the same encoder settings, or trying to, because the video is decompressed and sent to the encoder. You'd use the desired settings for the new encoder because it's oblivious as to whether the video has been encoded before. It just sees the raw, decompressed video. It's a bit like decoding an MP3 as a wave file (decompressed version), and then re-encoding the wave file as an MP3 again. The mp3 encoder just sees the wave file and is oblivious to how it was encoded originally. The higher the bitrate you use for the new MP3, the more it'll sound like the wave file. If the original Mp3 used a low bitrate and doesn't sound great, using the same bitrate again will make it sound worse. Video encoders are like lossy audio encoders in that respect. They throw information away.

You'd keep the frame rate, remove the black bars, and you can use the same encoder again if you want to, but you'd want to use the settings and an appropriate bitrate for the encoder to reproduce the video at a visually similar or equal quality, which doesn't necessarily mean using the same settings (or even the same encoder) as before.

Maybe try Vidcoder or Handbrake. You can crop the black bars and encode at a decent quality using the x264 encoder (you haven't even specified what the original encoder or codec was). x264 is the most commonly used encoder for that sort of thing these days. Those programs are fairly simple to use, but post back if you need help with them. I don't use them myself, but others here do.

Do you actually watch the video any other way than fullscreen? If you don't, then unless you have a display with an aspect ratio other than 16:9 (1920x18080 etc) there's probably not much point to re-encoding solely for the purpose of removing the black bars.

Thanks, sorry for the mistake: I meant 816! The problem with the black bars is that when I take a screenshot using VLC it also takes the black bars, and the subtitles too behave weirdly: I know you can modify their position tho. I've downloaded the 265 version to save space, wouldn't removing the black bands decrease the file size even more?

[jagabo]

Clean black letterbox bars don't consume much bitrate. You can only decrease the quality of the video by reencoding it.

MKV does have cropping parameters. You could try remuxing (no loss of quality) using those to have the player crop at playback.


[Attachment 53002 - Click to enlarge]

Don't count on all players obeying those parameters.

[MC23]

Clean black letterbox bars don't consume much bitrate. You can only decrease the quality of the video by reencoding it.

MKV does have cropping parameters. You could try remuxing (no loss of quality) using those to have the player crop at playback.


[Attachment 53002 - Click to enlarge]

Don't count on all players obeying those parameters.

Mh this is an interesting feature I didn't know about, thanks