Self-made DVD's from DVD recorder showing interlacing lines on HDTV - why?

[_Al_]

Are you sure it is actually on the DVD as 29.97p and not just 59.94 fields with each field recorded at the same moment in time?

Video checks as progressive and it was encoded as progressive, source was progressive as well, mediainfo reports scan type as progressive but also reports scan order top field first, because HcEncoder has that in its settings, you cannot disable that thing in there even if encoding as progressive. So something might be happening behind scenes, this flag game, you can check it yourself downloading that small VIDEO_TS, but video is progressive.

[jagabo]

To avoid VFR output the decoder performs the pulldown to produce CRF at 29.97 interlaced fps.

If it does not specify VFR then is does not make any sense.

The DVD spec is inherently VFR as far as the encoded frames are concerned. Only the final output is fixed field/frame rate.

[newpball]

I am beginning to wonder if to some actually distinguish between a progressive/interlaced source and how this source is actually encoded on a DVD.

[manono]

Still that does not answer the question why I have to IVTC those "progressively encoded" sources.

If they have to be IVTC'd then they weren't progressively encoded - you'd be able to 'Forced Film' them in DGIndex and get a progressive 23.976fps video with which to work. Maybe whatever it is you're using to play the video outputs the interlaced 29.97fps.

If you set DGIndex for its default 'Honor Pulldown Flags', then of course you get the interlaced 29.97fps video, whether it was originally soft telecined, hard telecined, or true video.

Most MPEG 2 decoders will perform the pulldown while decompressing frames.

Another piece of brilliance I suppose. Why on Earth would an MPEG-2 decompressor on a PC do that?
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I am lost for words....

No, you're just ignorant. At least that's better than being stupid. Maybe you'll get it in the end.

[newpball]

If they have to be IVTC'd then they weren't progressively encoded

Seems to me that flags make out an integral part of the encoding.

So we encode a progressive source then ignore the flags and then claim "see DVDs support progressive MPEG-2"?

Okay, this is going nowhere!

DVDs fully support progressive encoding!


It's new to me but you learn something new everyday!

[manono]

Geez, maybe this will help to explain. Note the flags (Progressive_Frame, True or False, Picture_Structure, Frame or Field), and how the flags tell the player how to output the fields:

http://www.hometheaterhifi.com/volume_7_4/dvd-benchmark-part-5-progressive-10-2000.html

The whole article is worth reading several times until you begin to understand. It was written a number of years ago and since then many many more DVDs are progressively encoded.

[newpball]

Geez, maybe this will help to explain.

Dear manono, there is no need to explain anymore, I am convinced and bow to superiority,

DVDs fully support progressive encoding!


I was totally wrong, sorry for all the trouble.

[newpball]

Are you sure it is actually on the DVD as 29.97p and not just 59.94 fields with each field recorded at the same moment in time?

Video checks as progressive and it was encoded as progressive, source was progressive as well, mediainfo reports scan type as progressive but also reports scan order top field first, because HcEncoder has that in its settings, you cannot disable that thing in there even if encoding as progressive. So something might be happening behind scenes, this flag game, you can check it yourself downloading that small VIDEO_TS, but video is progressive.

Yes, I checked and verified, can't get any more progressive than that!

And all completely conform the DVD standard!

Great and how wrong I was!

[jagabo]

mediainfo reports scan type as progressive but also reports scan order top field first, because HcEncoder has that in its settings, you cannot disable that thing in there even if encoding as progressive.

In MPEG 2 video the field order is flagged by a single bit in a fixed structure. So it has to have a value, and that value con only be 0 or 1. In the MPEG spec it is called top_field_first. When set to 1 the top field should be output first (even if the frame is progressive and it doesn't matter which field you see first). When it is 0 the bottom field should be output first.

[pippas]

Been doing some more testing of the DVD's tonight and have run into more issues! I wonder if this is relevant to the problems I have been having?

About 5 mins before the clip I posted as a sample there is a section of video where the camera is pointing into the sky. It pans about a bit and the screen if basically full of blue and white sky. I have noticed that when played back on a Toshiba SD1015KB DVD player (that can only output via SCART even though it says 'HI-RESOLUTION PROGRESSIVE' on the top of it) I get pulsing noise on the screen. The best way to describe it is like MPEG artifacts flashing in a routine pattern maybe half a second apart. I have looked closely at this same part of the video on my Sony DVD recorder outputting at 576i via SCART and the PS4 outputting at 480p via HDMI and I can't see this issue. It may be there but it's not as clear or visible to my eyes like it is on the Toshiba. This Toshiba was only cheap and probably isn't very good but I thought this may be relevant.

I do remember seeing something like this years ago when I played these DVD's back on an old version of Cyberlink DVD on my PC but I remember that if played on VLC the issue wasn't there. That only seemed to happen on dark areas of the screen, but this seems to be obvious on brighter sections of the screen I wonder if my high bitrate is causing this on some players or is this something fairly common?

As you will have realised, this thread has rather been hijacked at the moment, by the discussion on progressive DVD encoding. I'm afraid you'll have to just let the 'usual suspects' argue among themselves on this one for a while (there's only a few of them --it's always the same names! ).
Once that's died down, you may get a reply to your later posts (I only just saw this one, buried in the middle of this 'new' discussion). What you may have now realised is just how much variation there is between the way different DVD players ( and indeed TVs) can present your video.

As you already know, the video clips themselves seem fine. As most folk here have already suggested, probably the best option is to de-interlace, and re-encode your video. For improved results, probably not onto another DVD, I suspect......although you might give some thought to what other options for replay you need to consider?.....

[jagabo]

I did notice one unusual thing about the M2V sample: only one of the 31 GOPs has b frames. That's not illegal for DVD but it is unusual.

[JonVic]

Thanks pippas. Yes, my comments a while back do seem to have got a bit lost That's okay. Thanks for your input, yes it's amazing how different players are really considering they are designed to play one type of media!


@jagabo: That sounds a bit worrying! So there is something unusual/wrong with the DVD's after all? Maybe this is what is causing the issues and not poor equipment?

[jagabo]

@jagabo: That sounds a bit worrying! So there is something unusual/wrong with the DVD's after all? Maybe this is what is causing the issues and not poor equipment?

It's unusual. But as far as I know it's not outside the DVD spec.

[JonVic]

I wonder what would cause my DVD recorder to record in this unusual way? Good that's it's not outside the DVD spec. but maybe this is why the players struggle with the interlacing issue because it's not a usual scenario for them to deal with?

Just had a quick look online to try and understand more about this and it seems that each GOP should have b frames so that's very weird. Looks like this could be causing some issues.

[JonVic]

Just looked at the Apple website and it says this:

Things to Consider When Choosing a GOP Setting
You need to consider the following factors when choosing a GOP setting.

GOP Structure
This setting specifies whether there will be two, one, or no B-frames between the reference frames within a GOP. GOP structure, along with GOP size, determines the number of I-, P-, and B-frames that will be used during transcoding.

So it is possible that no b frames are needed within a GOP, have I read this correctly? How does the lack of b frames affect the video?

[jagabo]

Just had a quick look online to try and understand more about this and it seems that each GOP should have b frames so that's very weird

GOPs don't have to have b frames. The general idea is that b frames are encoded at a lower quality. You generally don't notice that drop in quality because an i or p frame comes along soon and restores the quality. I don't see why the lack of b frames would cause a player to have problems -- especially if it's limited to a lack of deinterlacing. I suppose the high bitrate (9300 kbps in your case) and the lack of b frames on recordable media might give some players problems. Recordable media is harder to read than pressed media so it's usually recommended that you stay below the maximum allowable bitrate. But again, not deinterlacing isn't what you expect if that's the problem. You expect the video and audio to stutter and break up in to macroblock decoding artifacts.

Keep in mind that recordable DVDs don't last forever. I would try coping the disc to a new disc with ImgBurn and see if the new disc works any better. Use quality media like Verbatim DataLife Plus or Taiyo Yuden.

[JonVic]

Just had a quick look online to try and understand more about this and it seems that each GOP should have b frames so that's very weird

GOPs don't have to have b frames. The general idea is that b frames are encoded at a lower quality. You generally don't notice that drop in quality because an i or p frame comes along soon and restores the quality. I don't see why the lack of b frames would cause a player to have problems -- especially if it's limited to a lack of deinterlacing. I suppose the high bitrate (9300 kbps in your case) and the lack of b frames on recordable media might give some players problems. Recordable media is harder to read than pressed media so it's usually recommended that you stay below the maximum allowable bitrate. But again, not deinterlacing isn't what you expect if that's the problem. You expect the video and audio to stutter and break up in to macroblock decoding artifacts.

Keep in mind that recordable DVDs don't last forever. I would try coping the disc to a new disc with ImgBurn and see if the new disc works any better. Use quality media like Verbatim DataLife Plus or Taiyo Yuden.

Thanks for the info. Yes, thinking about it more I suppose it's unlikely that it would cause problems with interlacing lines. As I mentioned a few posts back I have had this pulsing issue on dark areas with some software players and I have had pulsing on my cheapo Toshiba DVD player in lighter areas. I wonder if this is caused by the lack of b frames. However as I mentioned last night this doesn't happen on my DVD recorder, PS4 or really really cheap and old Cinetec DVD player.

The breaking up you mention I have seen on my Toshiba player when I burn the DVD files to TDK recordable media. The player sounds like it is running roughly and after a few minutes chokes, breaks-up the picture and then continues. If I burn them to Sony media I don't think it does the same (haven't done an extensive test on the Sony discs though). I don't seem to get any breaking up on the PS4 or Sony DVD recorder and as far as I know the Cinetec is okay too with both brands of DVD disc.

This Toshiba I have isn't great but it was the cheapest one in Tescos aside from the Tesco own brand one which I steered clear of!

[pippas]

One other option you might try......take one of the .VOB files from your existing DVD and copy it to a USB stick. According to the spec for your TV, the 'media player' supports VOB files (along with loads of other formats) . So you should be able to play the file by plugging in the USB into the TV. That would completely remove any problems introduced by any DVD player involved...just to see if it looks any better...

[JonVic]

One other option you might try......take one of the .VOB files from your existing DVD and copy it to a USB stick. According to the spec for your TV, the 'media player' supports VOB files (along with loads of other formats) . So you should be able to play the file by plugging in the USB into the TV. That would completely remove any problems introduced by any DVD player involved...just to see if it looks any better...

I have totally missed that function on my TV, I had no idea it could do that! Really surprised that it supports VOB files! Funny that it doesn't support MPEG2 and only plays it as a VOB file. I will need to get my hands on a USB stick. Will try and grab one in the next couple of days and give that a try. Thanks for the advice

[JonVic]

Coming back to this thread after a bit of a break. Unfortunately I just haven't had the chance yet to test using the built-in media player on the TV as I have been away a lot since last posting.

I am going to try in the next couple of days but before I do there is one thing that is still bugging me and although I mentioned it before I never got a direct reply as there were other things we were discussing.

When I output 576i over HDMI from my Sony DVD recorder the picture is grainier than if I output 576p, 720p, 1080i or 1080p. I don't get the interlacing lines as mentioned but the overall picture quality is just a bit grainier.

Likewise if I play the DVD on a cheaper player that only has SCART output the quality is the same as the 576i on the Sony DVD recorder (grainier). I believe this cheap DVD player will be outputting 576i as well?

The PS4 only outputs progressive in SD resolution so is irrelevant for this issue.

I don't understand why when the DVD recorder and cheap DVD player are outputting the DVD's native resolution and (I assume) letting the TV do the de-interlacing I get this grainier image but with no interlacing lines. Surely it should look better or the same as 576p if I am outputting 576i - not worse? Or is the de-interlacer in the TV to blame?

[jagabo]

I don't understand why when the DVD recorder and cheap DVD player are outputting the DVD's native resolution and (I assume) letting the TV do the de-interlacing I get this grainier image

SCART = analog
HDMI = digital

The TV has different processing for the two.

[JonVic]

Yes, that's what I had read which just confuses me.

I should have mentioned that I can output 576i through SCART and HDMI on the DVD recorder and both give the same fairly grainy image quality. The cheap DVD player with SCART also gives the same grainy image quality.

So it seems that no matter if I send the signal by HDMI or SCART and whether it's my DVD recorder or cheap DVD player 576i will always give the same fairly grainy image quality.

But if you play the same DVD on the DVD recorder or PS4 and output in progressive or 1080i I get some interlacing problems but the picture looks much cleaner!

This is really confusing

So, in summary this is what I get picture quality-wise:

Sony DVD recorder:

576i (via SCART) no interlacing lines but image looks a bit grainy
576i (via HDMI) no interlacing lines but image looks grainy (same as via SCART)
576p Picture is noticeably sharper with less grain but interlacing lines show-up
720p Picture is noticeably sharper with less grain but interlacing lines show-up
1080i Picture is noticeably sharper with less grain but interlacing lines show-up
1080p Picture is noticeably sharper with less grain but interlacing lines show-up

Toshiba cheapo DVD player

576i (via SCART) no interlacing lines but image looks a bit grainy (same as Sony DVD recorder with HDMI and SCART output)

I hope this thread hasn't been abandoned now as it got very long and someone can still help me understand this. My solution for watching the DVD's was to watch them in 576i until I got better equipment as suggested but it really bugs me that 576i is always grainy. Surely something is wrong here, this can't be right?

[Cornucopia]

If you are actually serious about troubleshooting this, you need to test your disc on a completely different system-especially a different TV. You also need to be clearer about vague terms such as "grainy". Do you mean noisy, pixellated, fuzzy/soft? Is the grain a static pattern or is it random, etc.?

Scott

[jagabo]

So it seems that no matter if I send the signal by HDMI or SCART and whether it's my DVD recorder or cheap DVD player 576i will always give the same fairly grainy image quality.

But if you play the same DVD on the DVD recorder or PS4 and output in progressive or 1080i I get some interlacing problems but the picture looks much cleaner!

Then it's just different processing (by the player and/or the TV) of the 1080i signal. Players and TVs perform all kinds of filtering when upscaling and displaying video.

[JonVic]

So it seems that no matter if I send the signal by HDMI or SCART and whether it's my DVD recorder or cheap DVD player 576i will always give the same fairly grainy image quality.

But if you play the same DVD on the DVD recorder or PS4 and output in progressive or 1080i I get some interlacing problems but the picture looks much cleaner!

Then it's just different processing (by the player and/or the TV) of the 1080i signal. Players and TVs perform all kinds of filtering when upscaling and displaying video.

Sorry, I have read your message a few times but I don't quite understand. I'm not seeing any problem with the 1080i signal. When the DVD is played back 1080i it has the same clarity and picture quality as 576p, 720p and 1080p. It looks fine. It's when I play back in 576i that things look grainy. That happens regardless of whether it is through HDMI or SCART and no matter which player I use.

The 'grain' is like composite quality video compared to RGB.

[JonVic]

If you are actually serious about troubleshooting this, you need to test your disc on a completely different system-especially a different TV. You also need to be clearer about vague terms such as "grainy". Do you mean noisy, pixellated, fuzzy/soft? Is the grain a static pattern or is it random, etc.?

Scott

I'm very serious about troubleshooting this. I can of course go into more detail but wanted to ask the question first of all in case someone said "576i will always look worse than 576p" and then I would have saved myself a lot of time evaluating the video. It seems that isn't the case so I will have to try and examine the video more closely as well as try to find access to another HDTV which i'm not sure how I will do that but will see what I can do.

As far as grainy goes, I think it would best be described at this stage as like when you switch from RGB to composite quality. It just looks poorer overall quality.

[JonVic]

By the way, it may or not be relevant but on my DVD recorder it has four colour output methods for HDMI. These are:

RGB 0-255
RGB 16-235
YCbCr 4:2:2
YCbCr 4:4:4

What is interesting about this is if you select 576i you cannot select YCbCr 4:2:2. You can only select the other three. If you choose any other resolution from 576p upwards you can choose from all four. Does that indicate that 576i has different 'properties' to the other resolutions. I am just trying to work out if this lack of quality for 576i through HDMI and SCART is normal really and if this shows there is something fundamentally different about it compared with the others.

I'm looking into converting these as per previous suggestions but I would like a workable DVD solution if possible and as I have the interlacing issues on things at 576p and above 576i was a good option, it's just this odd lack of quality that confuses me.