Interlaced/progressive quickly alternating

[wlibero]

Hi,

I thought the other forums are not appropriate (,right?).

For my archive, I'm recording from my DVB-S TV card (MPEG-2, German TV Station "VOX" in this example) and transcode it. Transcoding isn't the issue here; I know how to do it. Sometimes stations broadcast progressive, sometimes interlaced. It's easily visible whether I have to apply a deinterlace filter.

My problem: This time I'm not sure because some parts are i, some are p, and it quickly changes within few seconds throughout the whole recording. For example, 7 progressive frames, followed by 7 interlaced, followed by 7 progressive frames. I'm not kidding!

As the original container format is TS, I use ProjectX for demuxing. The log file says:
-> GOP summary: min. 18, max. 42 fields; contains interlaced frames
If there were also progressive frames (or flagged as progressive), ProjectX would have logged it.

Well, what is my question?......... What do you think about this? I don't want to apply deinterlacing manually to 1001 small parts. Is the station trying to fool us intentionally by making it harder to process it? Haven't had this problem yet.

Thx for your thoughts.

[manono]

What do you think about this?
Nothing much. Not unless you provide a sample if you can't figure it out yourself. If you don't see interlacing, it's not interlaced.

If parts of it are truly interlaced, you can use a 'conditional' deinterlacer, one that only deinterlaces those frames seen to be interlaced. Ones such as TDeint(Full=False) or Vinverse.

However, there are other possible reasons you might get that changing back and forth between interlaced and progressive encoding and where using a deinterlacer would be unnecessarily degrading to the video. Again, a sample will prove useful.

[wlibero]

Nothing much. Not unless you provide a sample if you can't figure it out yourself. If you don't see interlacing, it's not interlaced.
I can figure it that it's both. Interlaced, progressive, interlaced, progressive, interlaced, progressive,.... That's the issue.

If parts of it are truly interlaced, you can use a 'conditional' deinterlacer, one that only deinterlaces those frames seen to be interlaced. Ones such as TDeint(Full=False) or Vinverse.Ok, thanks!

Again, a sample will prove useful.For copyright reasons I think I can't provide a sample, can I? Or you can just believe me! :)

........
I've cut a small part. No filter was applied. I've set speed to 1 FPS so that it's visible. Look at the edge of the horizontally moving elevator door:

http://www.file-upload.net/download-3761713/test.zip.html

(There are better examples in the original but I wanted to show something neutral, not faces....)

[manono]

For copyright reasons I think I can't provide a sample, can I?
Yes, you can. And please make the sample from the source MPEG. But yes, I do see the interlacing. 10 seconds with steady movement will be plenty.

[TheSkiller]

For example, 7 progressive frames, followed by 7 interlaced, followed by 7 progressive frames.
I've seen similiar things myself on movies broadcasted on private German TV stations. Sometimes they like to speed up movies so that they fit their preferred schedules. When the movie is speed up, it can result in something like 7 progressive frames followed by 7 interlaced ones...

If that's the case for your recording then things get pretty nasty because no matter what you do to deinterlace the footage you will always be left with bumpy/uneven motion. Then I personally would either leave it as is in MPEG2 or discard the recording and buy or rent the DVD (if available).

[wlibero]

Yes, you can. And please make the sample from the source MPEG. But yes, I do see the interlacing. 10 seconds with steady movement will be plenty.The sample is fine, you see it like I do and that's sufficient.

[wlibero]

I've seen similiar things myself on movies broadcasted on private German TV stations. Sometimes they like to speed movies up so that they fit their preferred schedules.
Yes! You've noticed this too! I wasn't aware of it til last week. Up to 9% difference between 1st and 2nd transmission. I was pretty suprised, but I also supposed it's for the schedule.
When the movie is speed up, it can result in something like 7 progressive frames followed by 7 interlaced ones...Had these speeded up transmissions already but without that effect, but, hey, there's always a first time.

...and buy or rent the DVD (if available).oh, I didn't know! ;) (i didn't complain btw, just curious)

Anyway, thanks guys, just wanted to talk about this detection.

[manono]

The sample is fine, you see it like I do and that's sufficient.

I see it very differently than you do and think it can be handled without much, if any, use of a deinterlacer. But I'd like to see a raw sample just to be sure.

What do you wish to do with it - what's your intended output format?

[manolito]

Another way to treat such videos is to use HCEnc in AutoDeinterlace mode. HC will determine by itself if the source is interlaced or progressive and switch from progressive settings to interlaced settings automatically.


Cheers
manolito

[Didée]

Oh, are they STILL DOING THIS CRAP?!? That's time stretch. Intention: to be allowed to place more advertisements during the show. :rolleyes:

(General principle with fantasy numbers: If a show is shorter than XX minutes, the station may place e.g. 15 minutes of advertising. If a show is longer than XX minutes, the station may place e.g. 30 minutes of advretising. Now, if the show is just one or two minutes shorter than XX, then there is the obvious $$$ wish to make the show longer...
From my observation, TV stations have mostly switched to the "repeat last scene before/and/after the ad break" strategy.)

What you would have to do is: find all the affected sections, perform Fieldmatching+Decimation on them, AND adjust audio speed/pitch. Finally splice with the clean sections again.

In short: it's not worth the effort. Either leave it as it is, or just cram it in the trashbin. :devil:

[wlibero]

I see it very differently than you do and think it can be handled without much, if any, use of a deinterlacer. But I'd like to see a raw sample just to be sure.I'm really sorry, but as I'm not sure about the statutory provisions (right words?) concerning copyright, I don't provide the original sample. I ask for your understanding.

What do you wish to do with it - what's your intended output format?I'm just playing around. I'm using AviDemux to cut the commercials (frame exactly) and transcode to H.264 (setting CRF=22). The result is for my own archive. But it's unimportant. I will probably never watch it again. Why do I do it? Because I can! It's fun to see the small file size without commercials and transcoded from MPEG-2 to H.264. (And, no, I don't want to buy a new hard drive even if it's cheap nowadays, because I don't need it.) Audio channel is just copied. Target container is MP4 if audio is MP2 and MKV if it's AC3 (5.1 channels). That's the whole unintersting story. :)

I was only asking because of this never-before-seen quick switching between p and i frames (EDIT: better: frame sequences)

Thanks anyway.

[wlibero]

Another way to treat such videos is to use HCEnc in AutoDeinterlace mode. HC will determine by itself if the source is interlaced or progressive and switch from progressive settings to interlaced settings automatically. Thanks also.

[wlibero]

In short: it's not worth the effort. Either leave it as it is, or just cram it in the trashbin. :devil:Right, it's not worth the effort. Correcting playback speed wan't my intention anyway. The effect was mentioned by TheSkiller and I agreed.