Interlaced or Deinterlaced when viewing on PC mon ?

[jusko]

Most people say that a video should be deinterlaced or progressive when viewing on a computer monitor. I rendered some DV footages to format MP4, H.264 progressive and viewed on my PC mon. The video was quite jerky no matter what players were used.
If I rendered the same footages with format MP4, H.264 but in the original lower field first, the video was very smooth like the original avi files.
I have tried using AE, PPro, and PowerDirector7, but the results were the same, i.e. Progressive > jerky, interlaced > smooth. I have also tried using other formats and codecs such as MPEG2 and WMV, the results were also the same.

Am I missing something ? Please advise.

Regards

[Guest]

What deinterlacer did you use to make the progressive video and what settings did you use? Please describe your complete process to make the progressive encode. With deinterlacing you can lose some motion fluidity, but I wouldn't describe it as "jerky".

[jusko]

Thanks neuron2 for your reply.

Yes, I shouldn't say jerky, but a noticeable difference from the original source. If progressive video is not smooth, why use it ? Why not use an interlaced one ?

For me, there is no special process to make the progressive video, just in the export setting > field order > (none)progressive. The rendered video will be progressive.

I also tried using the Red Magic Bullet Frames, but the result was the same.

I have seen a lot of progressive videos on the web, and they were very smooth. Just wonder how to make that.

Please advise.

[Guest]

Yes, I shouldn't say jerky, but a noticeable difference from the original source. If progressive video is not smooth, why use it? Why not use an interlaced one? We've had 24 fps film in cinemas since the start. Have you heard people complaining about motion fluidity? If you have source where the motion is important, such as fast sports action, then interlacing can give you an effectively higher picture rate at the expense of some vertical resolution. But that doesn't mean progressive video is not smooth in general. And don't forget that there are progressive formats with the double picture rate also, e.g., 720P.

For me, there is no special process to make the progressive video, just in the export setting > field order > (none)progressive. The rendered video will be progressive. You lost me because I don't know what application those operations belong to.

I have seen a lot of progressive videos on the web, and they were very smooth. Just wonder how to make that.

Please advise. Tell me what application you use and describe your entire process. What is the nature of the source material?

[[P]ako]

My guess is that you are decimating when deinterlacing. You will need to blend the fields.

[jusko]

Thanks neuron2 and [P]ako.
Sorry I didn't make it clear. I did mention I used After Effect (AE), Premiere Pro (PPro)CS4 and PowerDirector 7 in my first post. In these video editors, you have the choice of selecting Progressive, upper field or lower field in the "Field Option" dialogue box of the export setting. But I don't know how these video editors do the deinterlacing, whether it blend the fields or discarding a field.
But if these internal deinterlacers are not good, how about the Magic Bullet Frames ? I also tried that but the resulting video still lacked the fluidity.

Any ideas please ?

[Guest]

Those apps are doing the H264 encoding too?

I advise you to do the deinterlacing using Avisynth.

If you post a small sample of the unprocessed DV, I will make a progressive encode and see if you think it is smooth enough.

[jusko]

Yes, H.264 and MPEG2 for encoding.

Here is an original PAL DV avi footage, please make an H.264 progressive video with all other parameters the same as the original i.e. 25fps, 720x576.
http://www.mediafire.com/file/jlungwmmmf1/175.avi

Thanks and Best Regards

[scharfis_brain]

without viewing that sample:
most consumer camcorders record with short shutter times resukting in non motion blurred images duuring moving sequences.
this yields into motion judder / Jerkyness.
either set your camcorder to record with a 1/50 seconds shutter or add artificial motion blur with a bob-deinterlacer, mvtools and a final selecteven().

but the best way to preserv the soomth motion of interlaced footage is to use a bob-deinterlacer and save the video as 50fps H.264.
this way you'll also benefit from the good quality offline deinterlacers compared to the realtime deinterlacers of your player/graphics adapter.

good quality bob-deinterlacers currently are:
yadif with nnedi
mcbob
tempgaussmc

[Guest]

I can't download it. It says "Your download is starting..." and then never starts.

[[P]ako]

It times out for me.

[2Bdecided]

Here is an original PAL DV avi footage, please make an H.264 progressive video with all other parameters the same as the original i.e. 25fps, 720x576.25 interlaced frames per second is 50 images per second.
25 progressive frames per second is only 25 images per second.
You can't expect the two to look the same.

You can easily create a 50 frames per second progressive version - no interlacing, perfectly smooth movement (well, identical to the source at least!).

Beware that many PCs can't display 50fps smoothly, so the result is not always as good as you might hope for.


The video embedded in this page is 25fps, the video in the "higher quality widescreen version" link underneath the embedded video is 50fps...
http://www.biggleswade.org/aog/stickyfingers.htm
(not your content, but you should get the idea!)

Cheers,
David.

[Jay Bee]

The video embedded in this page is 25fps, the video in the "higher quality widescreen version" link underneath the embedded video is 50fps...
http://www.biggleswade.org/aog/stickyfingers.htm






The player doesn't load the high quality version for me.

[2Bdecided]

No, me neither on one of my PCs - I haven't debuged it yet! You can click the little download arrow in the player though, and grab the file itself.

Cheers,
David.

[Jay Bee]

Yeah, download works. With the player working it would be a nice link to have handy for the next time someone claims that the difference between 25 and 50 fps is barely noticeable for most content...

[jusko]

I can't download it. It says "Your download is starting..." and then never starts.

I just tried downloading it and no problem. May be you have to allow the ads pop up before downloading.

@Scharfis_brain
Thanks and I'll try the deinterlacers you recommended.

@2Bdecided
Your 50fps video is very smooth and fluid.

I had tried making my progressive video 50fps, but also not as fluid as an interlaced 25fps.

Thanks anyway for your help.

[Jay Bee]

Here's a rar with three different versions of your file converted to x264 in mp4: 576i50 576p50 and 576p25

See which one you like best. The interlaced file should be as smooth as the p50 file if you use a decent decoder. I recommend Cyberlink.

http://rapidshare.com/files/167082334/jusko.rar

@2Bdecided
Your site works now in IE but not in FF.

[jusko]

Thank you Jay for taking time to do the testing :)

The 50i and 50p are both as smooth as the original DV footage, while the 25p is "stuttered". I think 2Bsecided is correct in saying that 25p will not be as smooth as 50i.

Now back to my original question, if 25p won't be as smooth as 50i, why most people say it is better to use make video progressive if viewed on computer monitor and interlaced if viewed on TV ? I find it no problem even if I play interlaced video on my PC monitor.

Best Regards

[poisondeathray]

I find it no problem even if I play interlaced video on my PC monitor.



Perhaps your software doing the deinterlacing then? Some are better quality than others

[Sagekilla]

Actually, this is dependent on a few factors.

On a computer monitor, where it's generally assumed you're playing back from your PC, the display requires progressive frames so your computer can: output as-is, bob up to 50p, or do smart bob to 50p (generally only if you have hardware acceleration). For a TV, if it's a CRT then it handles 50i natively. But, if it's anything else the display usually bobs it up to 50p or sometimes they have the smart bob for 50p.

You usually have better luck of getting the smart bob on a TV then on a computer.

[Jay Bee]

Now back to my original question, if 25p won't be as smooth as 50i, why most people say it is better to use make video progressive if viewed on computer monitor and interlaced if viewed on TV ?

I don't know why people say this. There's an assumption in there somewhere that computers aren't supposed to do deinterlacing during playback, probably because they weren't very good at it a few years ago. Nowadays there isn't really any difference between TVs and PC screens. Both can only display progressive signals. So TVs do deinterlacing using their onboard electronics while computers do deinterlacing using the GPU. The only problem is that the decoder on the computer has to tell the GPU to do deinterlacing but most decoders don't do this when their settings are left to default. That's why I recommended the Cyberlink decoder as its default setting is to let the GPU do the work.

Another reason people advise to deinterlace before encoding is because some people claim to not see much difference between 25 Hz and 50 Hz. So by not keeping the interlacing they can encode more efficiently and by not deinterlacing to 50p they can save a lot of file size.

Hope that clears it up a bit. But tbh I'm confused myself as to how people who spend pages and pages discussing the effects of psy trellis 1.0 vs 1.3 can at the same time care so little about something as fundamental as temporal resolution/motion fluidity.

[jusko]

Thank you all for your help :). I think I would keep the video interlaced as it is for the sake of fluidity and smoothness.

Best Regards

[2Bdecided]

Now back to my original question, if 25p won't be as smooth as 50i, why most people say it is better to use make video progressive if viewed on computer monitor and interlaced if viewed on TV ? I don't know why people say this. There's an assumption in there somewhere that computers aren't supposed to do deinterlacing during playback, probably because they weren't very good at it a few years ago. Nowadays there isn't really any difference between TVs and PC screens. Both can only display progressive signals. So TVs do deinterlacing using their onboard electronics while computers do deinterlacing using the GPU. The only problem is that the decoder on the computer has to tell the GPU to do deinterlacing but most decoders don't do this when their settings are left to default.Well, that's the issue, isn't it? If you're going to give the video to "normal" people (i.e. not us video obsessives) they won't have a clue about this - they'll just double click the file, play it in whatever the default player is (probably Windows Media Player) and if it plays at all they'll get visible interlaced stripes whenever there's movement.

I know it's format, codec and player dependent - but that's the point. Give someone a 25fps progressive file, and it's one less thing to go wrong.

(I thought a 50fps progressive file was safe, until I found a friends PC which couldn't cope, but didn't drop frames, so played the video slower than the audio!)

Cheers,
David.

[jusko]

Thank you very much David. You answered my question very clearly.

I have watched your 50fps progressive video and it was very fluid. I also tried to make a test video of 50fps progressive with Premiere Pro CS4. But the result was just as bad as 25fps progressive, i.e. stuttered.

David, could you tell me how to make a 50fps progressive video with Premiere Pro that is as fluid as yours please ? I have tried almost all settings and still couldn't make a fluid progressive video.

Best Regards

[2Bdecided]

I'm sorry jusko - I don't have Premiere Pro.

I'm doing my deinterlacing in AVIsynth, and dropping the AVS file into MeGUI for encoding to MPEG-4 AVC (x264). The AVIsynth script could be as simple as...

avisource("my_interlaced_clip.avi")
bob()
lanczosresize(640,480)

...in practice I'd use a better deinterlacer than bob, but that's a perfectly good start for testing. MeGUI will add converttoyv12() at the end if necessary.

Hope this helps.

Cheers,
David.

[jusko]

David, you have been very helpful, thank you very much indeed.:)

The software you mentioned seem very professional and require some technical knowledge on video editing. I am still a newbie and I will continue to acquire video editing knowledge from this great site :)

Best Regards