Advice regarding resolution change

[ioncube]

So I have a video file with following info:

Resolution: 720x576
Bitrate: 4200
Fps: 25

Now I want to convert it either to 16:9 or 16:10
My take on this is that 16:10 is better, this is why:
720/576=5/4
16/9-5/4=0.527777
16/10-5/4=0.35
Now 0.35<0.523 thus I assume that skew while changing towards a 16:10 is lower as opposed to 16:9 & thus I opted for a resolution of 640x400 with following x264cli

 x264 --crf 22 --level 3.1 --vf resize:640,400 --tune film --preset veryslow --deblock -2:-1 --acodec aac --abitrate 70 -o "d:\Trainers\_out.mp4" "d:\Trainers\out\in.wmv"

Also the original video is a bit grainy can you modify my cli to add any required filter?

[Case]

720x576 is a common resolution for widescreen (16:9) video on DVD and also used for DV video. Imho, that gives a movie with this resolution a likely correct display aspect ratio of 16:9, with the available information on the source.

[ioncube]

720x576 is a common resolution for widescreen (16:9) video on DVD and also used for DV video. Imho, that gives a movie with this resolution a likely correct display aspect ratio of 16:9, with the available information on the source.

well on my 19' 1440x900 the result is very poor

[hello_hello]

I agree it's likely to be 16:9.

I'm not sure I understand the logic behind your math. The formula is simply: Storage aspect ratio x Pixel Aspect ratio = Display Aspect Ratio. There's no fixed values for any of them. Well except......

If your video is standard 16/9 PAL DVD/mpeg2 video it'll use a standard PAL DVD/mpeg2 display aspect ratio. There's two of them. The official (ITU) way to resize the video isn't actually 1.77 (16/9). It's around 1.82. The "unofficial" method, which seems to be used pretty much all the time, is 16/9.

Generally when you resize video, especially when resizing to mod16 dimensions, it's unlikely you'll resize without some aspect ratio distortion. In order to minimise or eliminate it, you need to crop some of the video before resizing. In your case, cropping 2 pixels from one side of the video, then resizing to 624x352 will give you virtually no aspect ratio distortion. Assuming your original video is 16/9, you'd need to crop 36 pixels from each side before resizing to 640x400 if you don't want to distort the picture.

Have a play with this: http://www.mediafire.com/?09v9bldu9a6hm00 It calculates aspect ratio distortion for you while you adjust cropping and resizing. The "Use ITU-R Bt.601" checkbox lets you specify ITU or non-ITU resizing. If in doubt, uncheck it.

The bottom line though, is if you play the original video in one instance of a software player, then open the encoded version using another instance, the objects within each video should ideally look exactly the same. I suspect after resizing to 640x400 they won't. For the record, all software players I know of use 16/9 non-ITU resizing when displaying DVD video.

I'm quite partial to FluxSmooth for noise removal. The default FluxSmoothST(7,7) seems to work quite well. Obviously it's an AVISynth plugin. A Google for "avisynth plugin" will find you a whole variety of them. Keep in mind any noise removal tends to be a compromise between removing noise and retaining detail. Personally if it's just a "bit grainy" I'd leave it alone, but grain doesn't bother me as much as it seems to bother some people. Each to their own.....

x264's noise filter. I've never used it myself. http://mewiki.project357.com/wiki/X264_Settings#nr

[hello_hello]

well on my 19' 1440x900 the result is very poor

If you want help to improve a very poor result, you might need to put a little effort into defining what very poor means.

PS If it helps to explain why your math is flawed, NTSC and PAL DVD video both have a 16:9 aspect ratio, however the former uses a 720x480 storage aspect ratio, while for PAL it's 720x576. They both display as 16/9 however, as they use different pixel aspect ratios.
If memory serves me correctly, an NTSC 16:9 DVD resized to square pixel dimensions is around 854x480. For PAL it's 1024x576.

[jagabo]

720x576 may also be 4:3 DAR.

[ioncube]

My source video:

Video
ID                             : 1
Format                         : VC-1
Format profile                 : MP
Codec ID                       : WMV3
Codec ID/Info                  : Windows Media Video 9
Codec ID/Hint                  : WMV3
Duration                       : 9mn 29s
Bit rate mode                  : Variable
Bit rate                       : 4 121 Kbps
Width                          : 720 pixels
Height                         : 576 pixels
Display aspect ratio           : 5:4
Frame rate                     : 25.000 fps
Standard                       : PAL
Bit depth                      : 8 bits
Scan type                      : Progressive
Compression mode               : Lossy
Bits/(Pixel*Frame)             : 0.397
Stream size                    : 280 MiB (96%)
Language                       : English (GB)

Audio
ID                             : 2
Format                         : WMA
Format version                 : Version 2
Codec ID                       : 161
Codec ID/Info                  : Windows Media Audio
Duration                       : 9mn 29s
Bit rate mode                  : Constant
Bit rate                       : 128 Kbps
Channel(s)                     : 2 channels
Sampling rate                  : 44.1 KHz
Bit depth                      : 16 bits
Stream size                    : 8.69 MiB (3%)
Language                       : English (GB)

Output mp4

Video
ID                             : 1
Format                         : AVC
Format/Info                    : Advanced Video Codec
Format profile                 : High@L3.1
Format settings, CABAC         : Yes
Format settings, ReFrames      : 16 frames
Codec ID                       : avc1
Codec ID/Info                  : Advanced Video Coding
Duration                       : 9mn 29s
Bit rate                       : 1 213 Kbps
Maximum bit rate               : 2 806 Kbps
Width                          : 640 pixels
Height                         : 400 pixels
Display aspect ratio           : 5:4
Frame rate mode                : Variable
Frame rate                     : 25.000 fps
Minimum frame rate             : 14.085 fps
Maximum frame rate             : 90.909 fps
Color space                    : YUV
Chroma subsampling             : 4:2:0
Bit depth                      : 8 bits
Scan type                      : Progressive
Bits/(Pixel*Frame)             : 0.190
Stream size                    : 82.4 MiB (94%)
Writing library                : x264 core 125 r2200+677M 3a754e7
Encoding settings              : cabac=1 / ref=16 / deblock=1:-2:-1 / analyse=0x3:0x133 / me=umh / subme=10 / psy=1 / fade_compensate=0.00 / psy_rd=1.00:0.15 / mixed_ref=1 / me_range=24 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-3 / threads=3 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / fgo=0 / bframes=8 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=60 / rc=crf / mbtree=1 / crf=22.0000 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00
Encoded date                   : UTC 2012-10-27 11:04:04
Tagged date                    : UTC 2012-10-27 11:04:04

Audio
ID                             : 2
Format                         : AAC
Format/Info                    : Advanced Audio Codec
Format profile                 : LC
Codec ID                       : 40
Duration                       : 9mn 29s
Bit rate mode                  : Variable
Bit rate                       : 70.0 Kbps
Channel(s)                     : 2 channels
Channel positions              : Front: L R
Sampling rate                  : 44.1 KHz
Compression mode               : Lossy
Stream size                    : 4.75 MiB (5%)
Encoded date                   : UTC 2012-10-27 11:04:04
Tagged date                    : UTC 2012-10-27 11:04:04
Material_Duration              : 569121
Material_StreamSize            : 4980060

Calculator says my idea of resize dimensions was correct


What I want is to resize the video such that I won't get black bars at either side with minimum distortion

It looks satisfactory if one gets black at top & bottom but not left/right....
My set resolution of 640x400 apparently is another way of writing 16:10 but why even at this resolution the DAR is set to the original 5:4?
To be short I want a DAR of 16:10 which suffice minimum skew/distortion what will be x264cli

[jagabo]

Your calculations are meaningless. Since you're video has been reencoded and the original display aspect ratio information non longer exists there is no way to know what the proper DAR should be -- except by looking at the video. Showing a green box doesn't help. You need to find something with a known aspect ratio in the video and adjust accordingly.

[ioncube]

Your calculations are meaningless. Since you're video has been reencoded and the original display aspect ratio information non longer exists there is no way to know what the proper DAR should be -- except by looking at the video. Showing a green box doesn't help. You need to find something with a known aspect ratio in the video and adjust accordingly.

But this is where I am embezzled the original DAR still is retained in the video output though its output dimensions 640/400 coincides with 16/10!
You can see in the output video detail that aspect ratio is still 5/4 even though its dimensions are changed from 720x576 » 640x400

With all due respect I sincerely don't have the liberty to show video contents here or I could loose my job
I think I try --no-container-sar in x264cli

[jagabo]

It's extremely unlikely your video is 5:4 or 16:10 DAR. There are no devices that use aspect ratio. It's most likely your source is 16:9 or 4:3 DAR, common to most standard definition formats. But since you can't show the video nobody will ever know.

[ioncube]

If you say that it belongs no neither 16/9 or 5/4 what does the following line of 'MediaInfo' tells us:

Display aspect ratio           : 5:4

[jagabo]

If you say that it belongs no neither 16/9 or 5/4 what does the following line of 'MediaInfo' tells us:

Display aspect ratio           : 5:4

That's telling you there's no aspect ratio information in the source file so MediaInfo is assuming square pixels -- ie, it's assuming the display aspect ratio is the same as the frame size aspect ratio, 5:4. But that is almost certainly not the correct DAR since there are no common 5:4 DAR sources.

[ioncube]

Thnx for the info...
Can you now shed some light how we can specify a DAR with x264 syntax, thing like a force DAR of 16:9 or 16:10. In this instance e.g u want to 16:10 res

720/576 x a/b = 16/10 » a/b = 2/1  --sar 2:1

without any resize parameter

[poisondeathray]

Thnx for the info...
Can you now shed some light how we can specify a DAR with x264 syntax, thing like a force DAR of 16:9 or 16:10. In this instance e.g u want to 16:10 res

720/576 x a/b = 16/10 » a/b = 2/1  --sar 2:1

without any resize parameter

16/9 = 720/576 x 64/45

--sar 64:45

[ioncube]

16/9 = 720/576 x 64/45

--sar 64:45 = 1.28

oh! my bad.

720/576 x a/b = 16/9 » a/b = 64/45 = 1.422

now does that mean that 16:9 is better because of low sar value? To my knowledge sar is just the stretch (skew) factor

[poisondeathray]

16/9 = 720/576 x 64/45

--sar 64:45 = 1.28

oh! my bad.

720/576 x a/b = 16/9 » a/b = 64/45 = 1.422

now does that mean that 16:9 is better because of low sar value? To my knowledge sar is just the stretch (skew) factor

What do you mean by "better" ? "Better" would be what the original aspect ratio was . Otherwise things look distorted. Circles look like ovals. People look too fat or too skinny

--sar x:y is the sample aspect ratio in mpeg4 terminology . It used to be called "pixel aspect ratio" but they changed the naming terms

You can think of it as the w:h of the pixels

It's a linear equation, you just solve for the variable

[ioncube]

@poisondeathray
I really don't know the DAR of my input file, though details of it are already given above
The desire is to convert it somehow to 16:10 or 16:9 (with min. distortion) such that it don't display the way it displays now in my 16:10 lcd (screenshot above)

using

720/576 x a/b = 16/10 » a/b = 1024/625 = 1.28
720/576 x a/b = 16/9 » a/b = 64/45 = 1.422

I came to know that out of the two 16:10 provides min. distortion. Hope am clear

[poisondeathray]

There is no way to tell unless you measure a known object shot straight on, like a car tire

A green picture is meaningless, because there are no objects shown . You cannot assume the wmv had the correct AR in the first place, and Wmv definitely isn't the acquistion format or original distribution format - there might have been other errors introduced at multiple stages

If I were to guess - 16:10 probably produces worse distortion, but fills the screen display better. You're stretching it wider than it should be. It's most likely 16:9 content

It's pillarboxed (black bars on the left and right) because you're watching 16:9 content on a 16:10 display. IMO, distorting it is the wrong thing to do, but of course it's up to you . If you're going to do it that way, I think it's better to force the display to 16:10 in the player settings , or remux and force it in the container. When you use --sar x:y it's encoded into the bitstream level, not container level

[hello_hello]

Calculator says my idea of resize dimensions was correct

They are if your assumption the video is supposed to have a 16/10 aspect ratio are correct, but that's very unlikely.

How does the original video look? Do objects/people in it appear to be stretched vertically?
The reason I ask is because if the video is supposed to be 16:9 but it's displaying as 5:4 then it should be fairly obvious something is wrong. However if the video is really supposed to be 4:3 and the 16/9 or 16/10 aspect ratio was just your incorrect assumption..... well it may not be so obvious it's not displaying correctly if it's actually supposed to be 4:3. I'm starting to think maybe that's the case.... it's supposed to be 4:3.

Given the 720x576 resolution I think it's fairly safe to assume it should be either 4:3 or 16:9 to display correctly. I've seen lots of 720x576 (or NTSC 720x480) encodes which don't contain the correct aspect ratio information, so your video wouldn't be the first. If it is supposed to display as 4:3 try resizing it to 640x480, but you really need to use your eyes rather than make aspect ratio assumptions. If possible, try to find a straight-on shot of an object in the video which you know should be round. A car wheel or a clock face, that sort of thing. Which aspect ratio makes it look round?

Assuming the video is supposed to display as 4:3 and you want it to fill a 16:9 screen without distorting it, then according to the calculator you'll need to crop 72 pixels from both the top and bottom of the video to make it 16:9. Then depending on how close the resize dimensions you choose are to 16:9, you may need to crop a little more. It's a fair bit of picture to remove. I'm not sure why black bars top and bottom are satisfactory for you but down the sides they're not. The former is how wide screen video is displayed on a 16:9 screen while the latter is how 4:3 video is displayed on a 16:9 screen.

Of course it is possible the 720x576 resolution is just co-incidence and it's not actually supposed to be an encode of a PAL video and it's supposed to display as 5:4 but it's really fairly unlikely. Try 4:3 if 16:9 doesn't look right.

[jagabo]

The proper SAR for a 720x576 video with a 16:9 DAR is 64:45 if you go by MPEG/DVD rules. If you go by ITU rules (the 16:9 picture is in the inner 702x576 pixels, the rest is padding) the SAR is 16:11.

16/9 = 720/576 * 64/45
1.777 = 1.25 * 1.422
1.777 = 1.777


16/9 = 702/576 * 16/11
1.777 = 1.219 * 1.455
1.777 = 1.777

[manono]

You cannot assume the wmv had the correct AR in the first place...

I think you can pretty much assume the WMV doesn't have the correct aspect ratio. We can also assume this is the price you pay for downloading garbage from the internet made by clueless idiots. WMV is not the source format. Apparently ioncube has no understanding of DARs so this might help:

http://www.doom9.org/aspectratios.htm

I'd play it in a player that can change the aspect ratio so you can check which looks more 'normal'. MPC-HC is one such player. Open the video, right-click on the video and Video Frame->Override Aspect Ratio, and change back-and-forth between 16:9 and 4:3. It should be easy to tell the correct one.

[ioncube]

Thanks guys,

remux and force it in the container. When you use --sar x:y it's encoded into the bitstream level, not container level

can you tell me how do to it at 'container level'?
@manono
Yes I am beginner is this aspect & your link upon DARs stuff is a good read. Everyone who made me try to understand thanks to him. I will do reading & acquaint before I start asking questions. Thanks again

[poisondeathray]

can you tell me how do to it at 'container level'?

specify DAR with container eg. mkvmerge for mkv , mp4box for mp4 etc... If you demux and rewrap, you lose that information

encoding it into bitstream means it stays even if you demux - but if you're forcing the wrong AR . It's an "improper" thing to do