Help with pixel aspect ratio

[blue24]

Hi. I have some old footage in 720 x 576 resolution which should play back in 16:9 because of the pixel aspect ratio. However, after conversion in VD it plays back in 4:3. How can I force the file to play back in 16:9?

[LigH.de]

Answering questions would be so much easier if the questions didn't lack all the required details to understand them...

It depends on the video format or the container format, so please, more details about your encoding target. Usually you will set up a flag for your video codec or for your container multiplexer so that the player knows that it shall deskew the video to the desired target aspect ratio during playback.

In case "VD" means the original VirtualDub by Avery Lee, it will natively save only into the AVI container, which does not support aspect ratio flags. So your only chance would be that the video codec stores an aspect ratio flag (e.g. the Xvid codec does so); except you are using "external encoders", then you have to add command line options with an aspect ratio.

[blue24]

Answering questions would be so much easier if the questions didn't lack all the required details to understand it...

It depends on the video format or the container format, so please, more details about your encoding target. Usually you will set up a flag for your video codec or for your container multiplexer so that the player knows that it shall deskew the video to the desired target aspect ratio during playback.

In case "VD" means the original VirtualDub by Avery Lee, it will natively save only into the AVI container, which does not support aspect ratio flags. So your only chance would be that the video codec stores an aspect ratio flag (e.g. the Xvid codec does so); except you are using "external encoders", then you have to add command line options with an aspect ratio.

Hi. Unfortunately I know next to nothing about the technicalities of video conversion so you'll have to bear with me.

The original video format is MPEG. I've never really totally understood the concept of "containers" and whatnot so apologies if that isn't specific enough - MediaInfo just calls it an MPEG-PS file (it also lists it as being "720 x 576 16:9"). I'm only using VD so I can merge a bunch of these files together into one long, sequential video. I eventually plan on uploading the merged video file onto YouTube.

Yes, I do mean Avery Lee's original VirtualDub. Could you advise on "command line options"?

I was hoping there would be some sort of fix using the video -> filters -> resize menu inside VD, but evidently not?

[DB83]

Surely even VD has a resize filter.

The simplest method then is to resize your 720*576 mpeg2 file to a 1024*576 avi (check the maths)

[LigH.de]

The more we know about the source videos (at least technical details, but possibly even how they were originally made), the better we can suggest optimal conversion techniques. Showing us some MediaInfo reports in "Text" format (maybe archived as ZIP to be attached here if there are several) would not be the worst idea.

An MPEG-PS with 720x576 pixels sounds like the source might have been a DVD Video in PAL standard. Regarding your desired target format, we still know almost nothing... without selecting any codec, VirtualDub would possibly save uncompressed AVIs which can get huge, too big to upload them in sensible time.

A successor of VirtualDub is VirtualDub2. It offers a greater variety of codecs as well as containers, e.g. you could save AVC video (encoded by x264) in an MP4 or MKV container, that would allow you to save output files with a good ratio of quality and size, and a good compatibility to be handled by players or to be uploaded to YouTube. But using them optimally requires setting up several options. Just opening a source and saving a copy, without learning a lot in between, may disappoint you later on.

[jagabo]

Hi. I have some old footage in 720 x 576 resolution which should play back in 16:9 because of the pixel aspect ratio. However, after conversion in VD it plays back in 4:3. How can I force the file to play back in 16:9?

Set the pixel aspect ratio or display aspect ratio in the video codec's settings. Then hope your player supports the feature (not all do).

[blue24]

The more we know about the source videos (at least technical details, but possibly even how they were originally made), the better we can suggest optimal conversion techniques. Showing us some MediaInfo reports in "Text" format (maybe archived as ZIP to be attached here if there are several) would not be the worst idea.

An MPEG-PS with 720x576 pixels sounds like the source might have been a DVD Video in PAL standard. Regarding your desired target format, we still know almost nothing... without selecting any codec, VirtualDub would possibly save uncompressed AVIs which can get huge, too big to upload them in sensible time.

A successor of VirtualDub is VirtualDub2. It offers a greater variety of codecs as well as containers, e.g. you could save AVC video (encoded by x264) in an MP4 or MKV container, that would allow you to save output files with a good ratio of quality and size, and a good compatibility to be handled by players or to be uploaded to YouTube. But using them optimally requires setting up several options. Just opening a source and saving a copy, without learning a lot in between, may disappoint you later on.

Btw, apologies as I'm an idiot and I have been using VirtualDub 2 the whole time.

That's correct, it came from a 2007 ish era mini-disc camcorder (PAL). I've been saving in a "FFMPEG FFV1 lossless codec" which results in larger (but not unwieldy so) file sizes than the originals. Again I have no idea if that is a good idea or a good complementary codec etc! But to my eyes I cannot detect any degradation in quality between the original and the output.

[manono]

Again I have no idea if that is a good idea or a good complementary codec etc!

It's a good intermediate codec. It's not meant for a final format so it's useful only if you plan on doing some more work on it.

However, after conversion in VD it plays back in 4:3.

No, after reencoding by VDub it plays back as 5:4. 720/576=1.25=5:4. If the eventual aim is upload to YouTube, like DB83, I'd recommend a resize. Unfortunately, YouTube will show 480p and 720p and nothing in between. So, your resize choices are ~852x480 or 1280x720. Since you're using VDub2, convert to x264 with AAC audio inside the MP4 container.

[JVRaines]

I've been saving in a "FFMPEG FFV1 lossless codec" which results in larger (but not unwieldy so) file sizes than the originals. Again I have no idea if that is a good idea or a good complementary codec etc! But to my eyes I cannot detect any degradation in quality between the original and the output.

It's not a good idea because you are not gaining anything. You might as well just archive your MPEG-2 files. If your goal is to simply concatenate a number of these videos and upload them to YouTube, there is a way to do it at once without losing any quality whatsoever.

[manono]

That's a good point. Something like MPEG2Cut2 can join them all. Then you can upload the resulting MPG and YouTube will recognize the 16:9 DAR and resize it to 852x480. I think. It does that for the 4:3 720x480 MPGs I sometimes upload there, resizing them to 640x480.

[abolibibelot]

That's a good point. Something like MPEG2Cut2 can join them all. Then you can upload the resulting MPG and YouTube will recognize the 16:9 DAR and resize it to 852x480. I think. It does that for the 4:3 720x480 MPGs I sometimes upload there, resizing them to 640x480.

If it does not, adding the code :

yt:stretch=16:9

in the video's tags should correct the DAR – if that trick is still valid. Likewise, adding

yt:stretch=4:3

should display abnormally elongated 4:3 AR footage properly – a lot of videos on YouTube would no longer look like they were shot in the land of fat potato-faced people if that feature was better known (or maybe not, because many people simply don't see what's wrong, or don't care about the DAR).

[manono]

...if that trick is still valid.

It's not.

This feature is not available for videos uploaded after June 2016.

https://support.google.com/youtube/answer/146402?hl=en

[abolibibelot]

It's not.

Damn, then I gave an obsolete advice several times...
And what is supposed to replace it ?