Downrezzing Advice

[SameSelf]

Ringing as in "mosquito noise" after compression to MPEG2 or ringing like the ringing of a sharp resizer?

Maybe I am calling the artifact the wrong thing. But the thing that hurts my eyes is when the people on the left start moving, there are strange halos around each person. Kind of like a shimmering.

[_Al_]

My downscaling looks terrible!

You either create false sharp look with ringing or flickering (more flickering with interlace involved) or blurry image. Everyone prefers something else. This is SD, you go from 1080 down to 480. Not mentioning horizontal squeeze. Those rows, looking at standings, will be mess if I can guess. But I do not have lagarith in PC now to test your sample.

Do you still have a DV camcorder? I set up a situation, comparing DV footage with downresize. Downresize looked even better. Never looking back since. Making DVD is emergency situation, just use a simple resize, and be done with.

[SameSelf]

My downscaling looks terrible!

You either create false sharp look with ringing or flickering (more flickering with interlace involved) or blurry image. Everyone prefers something else. This is SD, you go from 1080 down to 480. Not mentioning horizontal squeeze. Those rows, looking at standings, will be mess if I can guess. But I do not have lagarith in PC now to test your sample.

Do you still have a DV camcorder? I set up a situation, comparing DV footage with downresize. Downresize looked even better. Never looking back since. Making DVD is emergency situation, just use a simple resize, and be done with.

Yes, I am beginning to think that given the nature of my video, I can only expect so much from a downscaled version. I just wanted to make sure there wasn't some tweak that I was missing. After playing around, the downscaling introduces the ringing, mosquito noise, or whatever it is called. I don't really care how the stands or the light poles look. I am only concerned with the people on the field.

Here are two encodes that I did. The first uses simple BilinearResize. The second is the BlackmanResize with 4 taps. Neither has any blurring or sharpening added. The BilinearResize seems to have less ringing around the people.

[Skiller]

There is loads of mosquito noise in those encodes (and that is related only to compression, not downscaling!). Looking at the file size alone reveals why: very low bitrate (around 1500 KBit/s is very low for MPEG2, even with a pretty static scene like this).

Have a look at my encode and see the difference.

[manono]

The Q-Scale indicator as seen in Bitrate Viewer is absurdly bad. It's an indicator of quality and they don't get much worse than that. Even though you seem to have set a max bitrate of about 9Mbps, neither even approaches that and the first sample has an average of 1.247Mbps and the second one 1.416Mbps. These numbers are absurdly low. Something is very wrong. Just how much are you trying to fit onto a DVDR? If it's only something like 90 minutes or so, then you figured the average bitrates needed to fill the disc very poorly.

[SameSelf]

Good eyes guys! I am not an advanced user of HCenc. This is really my first rodeo. I couldn't figure out why it was doing 1-pass encodes and not letting me set the bitrate. After unchecking the Constant Quantization box on Settings 1, I was able to set the bitrate to 8000. These definitely look better.

Now on another note, I was thinking maybe this is why there aren't many widesceen DVDs. There is just too much information to fit in such a limited SAR. So I tried the following which reduces the SAR that needs to be resized to 4:3.

AVISource("E:\SDTestRaw.avi", audio=false).AssumeFPS(30000,1001).ConvertToYV12(interlaced=false, matrix="rec601")
Crop(240,0,-240,0)
Sharpen(0.5, 0) #pre-sharpen horizontally to better keep hor. details
BlackmanResize(720, 480, taps=4) #for AviSynth versions before 2.58 use Spline36Resize
Blur(0, 0.7, false).Sharpen(0, 0.4, false) #medium, works well with almost any source in my experience

Attached are the re-encodes with the bitrate set to 8000. The first uses the crop and is encoded as 4:3 AR. The second has the crop commented out and is encoded as 16:9 AR (recall that this version really is 16:9; I just masked off some identifying information on the edges). IMO, the cropped 4:3 AR version looks better. I may tweak around with it some more, but I think I will be going with the cropped 4:3 AR workflow.

The Q-Scale indicator as seen in Bitrate Viewer is absurdly bad. It's an indicator of quality and they don't get much worse than that.

P.S. How do you enable the Q-Scale indicator in Bitrate Viewer? Mine only shows bitrate. Thanks so much!

[manono]

P.S. How do you enable the Q-Scale indicator in Bitrate Viewer? Mine only shows bitrate. Thanks so much!

Do you have the other one? The one to which I linked is the Tecoltd Bitrate Viewer 1.5.

[SameSelf]

Do you have the other one? The one to which I linked is the Tecoltd Bitrate Viewer 1.5.

Oh cool. Did not know about that one. I only have the freeware version. Thanks.

[SameSelf]

Well, after queuing up the encodes on my 70" HDTV (that is always the final check because the image is so big I can see every flaw easily) I truly prefer the cropped 4:3 AR. Fewer artifacts. I lose some of the field of view, but I think the compromise is worth it. I can't say in every case that this is the preferred workflow. But in this instance it worked nicely. The video is actually viewable and surprisingly good for an SD image.

[_Al_]

Constant Quantizer is still a valuable choice, something went wrong, I use Quant value (non-linear) set to 3 usually, default is 5 I think (which distributes less bitrate at the end), rest you might try to leave to default. Other than that you might have set something else to be not quite right.

[Skiller]

Post your HC.ini (settings).

[SameSelf]

It was set to 7 (non-linear) which I guess was some sort of default, idk. I always make sure to click "make DVD compliant". Anyway, I only have about 1 hour and 20 minutes of video that needs to fit on the DVD which gives me about 6500 bitrate.

[SameSelf]

Post your HC.ini (settings).

Pretty sparse if you ask me compared to all the switches and tabs in there.

*INFILE           e:\lagarithsd.avs
*OUTFILE          E:\DVD.m2v
*LOGFILE          E:\DVD.log
*BITRATE          6500
*MAXBITRATE       9000
*FRAMES           0 153015
*PROFILE          best
*ASPECT           4:3
*GOP              15 2
*DC_PREC          10
*PROGRESSIVE
*BFF
*FRAMELOG         psnr
*LASTIFRAME
*INTRAVLC         2
*MATRIX           mpeg
*PRIORITY         high

[KarMa]

I took jagabo's test pattern and made a video out of it, making sure to keep the 704x480 on the DVD. Picture below is a VLC cap, straight from the VOB file.



And then this is what it looks when I play the DVD on my cheap Sony DVP-SR200P DVD player, into my Hauppauge 1250 capture card over composite. It captures at 720x480.



It's not stretched as I had expected, but seems to automatically create the black bars on both sides. Behaving similar to just adding black bars to a 720x480 video.

This is what the Sony graphical splash screen looks like through my card, filling up nearly all the picture. https://forum.videohelp.com/images/imgfiles/egBqxI5.png . So the DVD player is certainly maintaining the AR, the way it is supposed to over composite. And if the DVD was played over HDMI it would not need to add black bars.

[_Al_]

1hour 20 min that is 2pass job, sure, I just was defending CQ type of encoding
my INI, not saying that it is best, anyway best setting for CQ is relative as you know, something like CRF number for x264, it is a quality choice which in result makes file bigger or smaller, ... ,just what I use for CQ:

*MAXBITRATE       8500
*PROFILE          best
*AUTOGOP          15
*CQ_MAXBITRATE    3.000
*DC_PREC          10
*PREVIEW
*INTRAVLC         2
*MATRIX           mpeg
*PRIORITY         normal
*WAIT             0

using cmd line, ..., command line arguments override INI file, if there is something set differently:

%Hcenc% -i "%temp_adr%_v.avs" -o "%temp_adr%.m2v" %field_order% -AUTOGOP 15 -CQ_MAXBITRATE 3 -AQ 2 -MAXBITRATE 8500 -aspectratio %DAR% -logfile "%temp_adr%_hc.encoder.log"

%field order% is -PROGRESSIVE or -INTERLACED -TFF or -INTERLACED -BFF (dv video)
%DAR% is 4:3 or 16:9

[Skiller]

So the DVD player is certainly maintaining the AR, the way it is supposed to over composite.

Yep, that is exactly what is supposed to happen.

And if the DVD was played over HDMI it would not need to add black bars.

Indeed, and that is exactly why I prefer 704x576/480 over 720x576/480 – it get displayed correctly no matter where. If you resized to 720 it also would be correct over HDMI (with most players it seems anyways), but Composite would not.

[jagabo]

It's not stretched as I had expected, but seems to automatically create the black bars on both sides. Behaving similar to just adding black bars to a 720x480 video.

Yes, players are schizophrenic. They follow the ITU spec at the composite output (probably because they use standard video DACs), the MPEG 2 spec at the HDMI output.

[manono]

Oh cool. Did not know about that one. I only have the freeware version.

The one you have is a different program entirely. I don't know why this one says 'Trialware' as I've never paid a penny for it. There is a commercial version, but I don't have it.

[SameSelf]

So the DVD player is certainly maintaining the AR, the way it is supposed to over composite.

Yep, that is exactly what is supposed to happen.

And if the DVD was played over HDMI it would not need to add black bars.

Indeed, and that is exactly why I prefer 704x576/480 over 720x576/480 – it get displayed correctly no matter where. If you resized to 720 it also would be correct over HDMI (with most players it seems anyways), but Composite would not.

Are we certain this is due to players being schizophrenic? As said earlier, both 704x480 and 720x480 (D-1) are legal DVD-Video formats for 4:3 AR. But for widescreen, only D-1 is legal. However, there could be some additional minutia around what is legal over composite versus HDMI and even RCA, not that those matter much anymore. I noticed that some of the current TVs in stores don't even bother with anything other than HDMI (likely due to royalty costs).

I wonder how jagabo's test pattern would perform for a widescreen version. I also have some commercial widescreen DVDs (just finished watching an old Christmas standard), but when I tried to use MediaInfo on the VOB it wouldn't tell me what the resolution was.

[Skiller]

As said earlier, both 704x480 and 720x480 (D-1) are legal DVD-Video formats for 4:3 AR. But for widescreen, only D-1 is legal.

I still doubt this as there is no valid proof of this (everyone keeps quoting that Wikipedia page), plus all widescreen DVDs I encoded, authored and burned myself over many years use 704 and not on a single player (old or new, cheap or expensive) did I ever experience any trouble with that.

I wonder how jagabo's test pattern would perform for a widescreen version.

Go ahead and test it (just flag it as 16:9 and re-author it, nothing else needs to be done), but I guarantee it's going to look identical when captured with your Hauppauge. There is no way it could be different. I would eat my hat if it was different.

[KarMa]

I wonder how jagabo's test pattern would perform for a widescreen version.

Go ahead and test it (just flag it as 16:9 and re-author it, nothing else needs to be done), but I guarantee it's going to look identical when captured with your Hauppauge. There is no way it could be different. I would eat my hat if it was different.

I forgot to mention that my captured image in post #74 was actually flagged as 16:9. This is what I got with 704x480 flagged at 4:3.



Don't know why the brightness is so different but they have the same black boarders.

[jagabo]

Here's a scope trace of a 720x480 4:3 DAR video playing on a DVD player (Philips DVP-5990) via composite:



Only the first ~5 percent of the scan line is displayed, from left to right. At the left is part of the horizontal sync pulse. To the right of that you can see the chromaburst signal. You don't see either of those on a normal TV. The number 0 corresponds to the first pixel of the 720 pixel wide DVD image, 8 is pixel number 8. The inset shows the corresponding portion of the picture that's being displayed on the TV. The source was 720 pixels wide with 8 pixel wide grey borders at the left and right edges. The middle 704 pixels are two pixel thick white and black vertical lines.

I didn't bother photographing it, but when displaying a similar 704x480 4:3 video with only the white and black lines (ie, the grey borders were removed before making the video) the lines were in exactly the same position and the 8 pixel wide grey borders were replaced with black borders by the player.

So this player follows the ITU spec at the composite output. When playing a 720x480 video the 4:3 image is contained in a 704x480 sub portion of the frame. With a 704x480 video the full frame corresponds to the 4:3 image. A TV would show exactly the same aspect ratio for both. If you could see the overscan area you would see the grey border of the 720x480 video, a black border (added by the player) with the 704x480 video.

As noted earlier, this differs from the upscaled HDMI output where both the 720x480 and 704x480 frames are upscaled to the full 1920x1080 frame -- leading slightly different aspect ratios.

[Skiller]

Thanks for all the efforts. It confirms what I observed myself when capturing the outputs of DVD-players.

As noted earlier, this differs from the upscaled HDMI output where both the 720x480 and 704x480 frames are upscaled to the full 1920x1080 frame -- leading slightly different aspect ratios.

Right, so the conclusion is: 704 is displayed correct for both analog SD outputs as well as upscaled HDMI (and software playback on a computer also). So why not show some more love for 704, guys?

[SameSelf]

Here's a scope trace of a 720x480 4:3 DAR video playing on a DVD player (Philips DVP-5990) via composite:

Only the first ~5 percent of the scan line is displayed, from left to right. At the left is part of the horizontal sync pulse. To the right of that you can see the chromaburst signal. You don't see either of those on a normal TV. The number 0 corresponds to the first pixel of the 720 pixel wide DVD image, 8 is pixel number 8. The inset shows the corresponding portion of the picture that's being displayed on the TV. The source was 720 pixels wide with 8 pixel wide grey borders at the left and right edges. The middle 704 pixels are two pixel thick white and black vertical lines.

I didn't bother photographing it, but when displaying a similar 704x480 4:3 video with only the white and black lines (ie, the grey borders were removed before making the video) the lines were in exactly the same position and the 8 pixel wide grey borders were replaced with black borders by the player.

So this player follows the ITU spec at the composite output. When playing a 720x480 video the 4:3 image is contained in a 704x480 sub portion of the frame. With a 704x480 video the full frame corresponds to the 4:3 image. A TV would show exactly the same aspect ratio for both. If you could see the overscan area you would see the grey border of the 720x480 video, a black border (added by the player) with the 704x480 video.

As noted earlier, this differs from the upscaled HDMI output where both the 720x480 and 704x480 frames are upscaled to the full 1920x1080 frame -- leading slightly different aspect ratios.

This is a sticky-worthy post. Thanks jagabo and KarMa for the tests. Great job!

Also, this was written up a while ago about why 720 even exists. Great summary.

post1692255

Click the link for the full quote. The relevant part is below:

Assume a square pixel 640x480 CCD which produces a 4:3 aspect image. For recording this will be oversampled to 704x480 (narrow pixels) for recording. When you receive 704x480 in a transmission or file, the player will rescale 704x480 to 640x480 for square pixel display. If you display as 704x480 on a computer monitor, you will see a 10% horizontally stretched picture.

ITU-Rec601 also provisioned for wide 16:9 recording also at 704x480. Assume a 854x480 16:9 square pixel CCD. For recording this will be undersampled to 704x480 (wide pixels) for recording. When you receive 704x480 in a transmission or file, the player will rescale 704x480 to 854x480* for square pixel 16:9 display. If you display as 704x480 on a computer monitor, you will see an 18% horizontally squished picture. The player sees a "wide" flag to tell it to scale display aspect ratio (DAR) as 4:3 or 16:9.

Today, all ASTC standard def video is still sent as 704x480 for 480i and 480p although 640x480 transmission is also approved.

So where did 720 come from? Video transmission is subject to horizontal picture shifts especially when it is repeatedly converted from analog to digital along the way. 8 pixels were added left and right to assure that the central 704x480 image was not side cropped by worse case horizontal shifts. At the final broadcast point, the 4:3 or 16:9 image is recentered horizontally and only the central 704x480 pixels are broadcast. The important concept is pixel aspect ratio (PAR) as broadcast for 704x480 and 720x480 is the same.

If you capture a 704x480 broadcast into a 720x480 raster, you get ~8 black pixels left and right as shown above whether the aspect ratio is 4:3 or 16:9. Image pixels lie in the central 704x480. You can crop off the side pixels and author a 704x480 DVD for perfect 4:3 or 16:9 playback on any DVD player. Or you can author and play the 720x480 capture file as 720x480 but the black side pixels will show. The black sides are usually not seen on a TV due to overscan but they may be seen with computer players.

If the Panasonic SDR-H200 is using a 704x480 raster, then all of the above applies to you. You should set a 704x480 project (4:3 or Wide), then encode and author a 704x480 DVD.

The DVD powers that be fully provisioned 704x480 and it's half width brother 352x480 as valid DVD formats. 704x480 can be 4:3 or wide. 352x480 is only supported for 4:3.

The DVD standard also allows a 720x480 with full horizontal content. This was used for commercial DVD and also by DV format camcorders. I'll try to describe that later.


* 16:9 calculates to 853.333x480 but most players stretch it out to 854x480 and then use that as a basis for upscale.

[hello_hello]

Also, this was written up a while ago about why 720 even exists.

Maybe it'd be better if it didn't exist, but in my opinion by far the majority of 16:9 PAL DVDs (and probably NTSC) have an exact 16:9 display aspect ratio compromising the entire 720 width. I've come to that conclusion after comparing many DVDs (or my DVD encodes) to their HD square pixel counterparts.

And all software players I know of resize to exactly 16:9 or 4:3, although I assume they'd do the same if the width was 704 rather than 720.

[SameSelf]

Maybe it'd be better if it didn't exist, but in my opinion by far the majority of 16:9 PAL DVDs (and probably NTSC) have an exact 16:9 display aspect ratio compromising the entire 720 width. I've come to that conclusion after comparing many DVDs (or my DVD encodes) to their HD square pixel counterparts.

And all software players I know of resize to exactly 16:9 or 4:3, although I assume they'd do the same if the width was 704 rather than 720.

Now that I have finished my BDMV/DVD project and handed them out as Christmas presents, and had some time to ruminate on things, watch the DVDs, etc., here is what I wrote up in another thread (https://forum.videohelp.com/threads/376165/post2426358) where this question popped up again:

It comes down to two things:

1. What does the authoring program accept? If the authoring package accepts 704 pixels wide as DVD compliant then, sure, give 704 all the love you want. DVD Architect accepts both 704 and 720, but I really see no point in choosing 704, a holdover from the analog broadcast days. If the authoring package considers 704 pixels wide non-DVD compliant and will transcode, you are stuck. You have no choice but to encode as 720 pixels wide. At this point it is up to you whether you want to add black borders or stretch the video. As for which one to do, refer to the next rule.

2. Does the display show the black borders? No way of knowing for sure without a test. Here is what my set up through a modern DVD/BD player, HDMI, and modern HDTV does: it displays the black borders. Ugh! So, going forward, if my authoring package forces me to encode as 720, I will be stretching the video because that is far more aesthetically pleasing than ugly black borders. This is of particular importance when downrezing HD content for DVD.

Optional Rule 3: So your dinosaur player and TV don't display the black bars/overscan area. Now your stressing about the edges of your image getting cropped if you stretch your 704 content. Your coming here for advice. You get confused and don't know what to do. Here is a tip. Embrace 720. One of these days the dinosaur player and TV will go to the dump, and it will be like a gift of 16 pixels that you never knew you had


Otherwise, this is a great thread. Tons of solid information from lots of contributors and should really be made a sticky.

[Skiller]

My opinion is, it's not as if you will be able to tell a difference in detail/resolution between 704 and 720 (without borders) when watching the thing on your TV, and considering, as we found out, 704 is displayed correctly in every scenario, I see no reason not to prefer it over 720.

If your authoring software doesn't accept 704 then I would question my choice in authoring software and then if I still wanted to use it I would just simply trick it by patching the first res header of the m2v file and fool the ignorant authoring software.

Honestly, the only place where I use 720x576 are the menus. Simply because some players don't place the button highlight subpics exactly where they belong when the underlaying menu is encoded in 704x576.

[hello_hello]

DVD Architect accepts both 704 and 720, but I really see no point in choosing 704, a holdover from the analog broadcast days.

Even though it appears a 704x576 resolution will always display the same way (ie correctly) it still isn't worth considering?

Does the display show the black borders? No way of knowing for sure without a test. Here is what my set up through a modern DVD/BD player, HDMI, and modern HDTV does: it displays the black borders. Ugh! So, going forward, if my authoring package forces me to encode as 720, I will be stretching the video because that is far more aesthetically pleasing than ugly black borders. This is of particular importance when downrezing HD content for DVD.

Are you saying your TV never overscans? Or that it can't overscan? Because that'd probably make it unique. One of a kind. As far as I know all TVs overscan broadcast pictures and generally you can't disable it. I'd have thought there was probably more chance a TV would always overscan than not overscan at all. I kind of remember my other half's old 720p LCD TV always overscans without an option to disable it, but I'd have to check again.

By the way, you forgot to mention some of the rules. I'll number these rules 4, 5 and 6 to avoid confusion, although when they're applied correctly rules 4, 5 & 6 make rules 1, 2 & 3 obsolete.

4. Don't author DVD video or create compliant DVD video discs. It hasn't been 1995 for many years. DVDs are a holdover from a bygone era when we needed a holdover from the analogue broadcast days, and their current usage should be strictly limited to authoring discs so grandma can watch the family videos.

5. You should be able to tell your DVD/Bluray player to connect to the TV at PAL or NTSC resolutions in which case the TV will upscale, and even if it won't over-scan at 1080p I'd be astounded if it doesn't over-scan for PAL/NTSC resolutions.

6. If your previous generation hardware won't allow you to control overscanning, don't use it. I never change the over-scan setting on my TV, because two taps on the "9" key gets MPC-HC to zoom in just enough to simulate over-scan, and tapping the "5" key resets it. If you're stressing about the aspect ratio, a single tap on the "6" key gets MPC-HC to stretch the video width by about 2.5% and for DVDs that's ITU. Before you know it you'll be enjoying ITU DVDs with an ITU aspect ratio and "generic" DVDs at exactly 16:9.
I know it's not a pleasant to think about it, but grandma isn't going to live forever, and all those DVD video discs will go to the dump because nobody will own a media player with an optical drive (and computer optical drives won't be common much longer due to the imminent demise of the desktop), and you won't know what to do with all the extra free time you have.... once you're no longer encoding everything twice to ensure you always have a 100% grandma compatible copy available.

Otherwise, this is a great thread. Tons of solid information from lots of contributors and should really be made a sticky.

You didn't account for rule 4. Make rule 4 a sticky and you won't need any others.

[SameSelf]

4. Don't author DVD video or create compliant DVD video discs. It hasn't been 1995 for many years. DVDs are a holdover from a bygone era when we needed a holdover from the analogue broadcast days, and their current usage should be strictly limited to authoring discs so grandma can watch the family videos...

...I know it's not a pleasant to think about it, but grandma isn't going to live forever...

...to ensure you always have a 100% grandma compatible copy available.

I detect some grandmother hate, not sure where it is coming from though.

[hello_hello]

I detect some grandmother hate, not sure where it is coming from though.

It's due to all the time I spent authoring DVDs just for grandma.

Was that a rhetorical question? Sarcasm can be hard to detect in forum posts.