Maintaining Y[0...255] and YUV411 in Avisynth

[LigH.de]

There is a fundamental difference between YUY2 or UYVY on one hand, and YV16 on the other hand: "packed pixel" vs. "planar" ordering of luminance and chrominance components across a frame. But this difference is only interesting for programmers...

[SameSelf]

So according to the Avisynth wiki here:

http://avisynth.nl/index.php/Sampling

v2.6 natively supports 4:1:1 DV. Would it be better for me to upgrade to v2.6, so I have complete control how to upscale my 4:1:1 DV to 4:2:2? For example, something like:

ConvertToYUY2(interlaced=true,chromaresample="spline36")

[SameSelf]

@ SameSelf:

Do you even know which video format AviSource(V) loads when you omit the parameter "pixel_type"? Please compare:

• AviSource(V).Histogram(mode="levels").Info()
• AviSource(V, pixel_type="RGB24").Histogram(mode="levels").Info( )
• AviSource(V, pixel_type="YUY2").Histogram(mode="levels").Info()
• AviSource(V, pixel_type="YV12").Histogram(mode="levels").Info()

PLEASE NOTE: Some variants above may provoke an error if the VfW codec handling your AVI file's video content does not support color space conversions while delivering the decoded video to the VfW API.

This is a puzzling/frustrating.

Here is what is reported for the above formats:

AviSource(V).Histogram(mode="levels").Info() = YV12
AviSource(V, pixel_type="RGB24").Histogram(mode="levels").Info() = ERROR: Histogram Levels mode only available in PLANAR
AviSource(V, pixel_type="YUY2").Histogram(mode="levels").Info() = ERROR: Histogram Levels mode only available in PLANAR
AviSource(V, pixel_type="YV12").Histogram(mode="levels").Info()[/list]= YV12

Deleting Histogram():

AviSource(V, pixel_type="RGB24").Info() = RGB24
AviSource(V, pixel_type="YUY2").Info() = YUY2
AviSource(V, pixel_type="YV411").Info() = ERROR: AVISource: the video decompressor couldn't produce YV411 output
AviSource(V, pixel_type="FULL").Info() = YV12

I guess I shouldn't be too surprised it defaults to YV12 since according to the AVISource wiki, YV12 supersedes YV411. But what I don't understand is why can't Avisynth open my DV when pixel_type = YV411. I checked my Avisynth install and I have 2.6 installed. And the supposedly v2.6 natively supports 4:1:1 content.

Any ideas what might be the problem?

Here is the mediainfo of the file:

General
Complete name               : D:\video.avi
Format                      : AVI
Format/Info                 : Audio Video Interleave
Commercial name             : DV
File size                   : 181 MiB
Duration                    : 50s 117ms
Overall bit rate mode       : Constant
Overall bit rate            : 30.3 Mbps

Video
ID                          : 0
Format                      : DV
Codec ID                    : dvsd
Codec ID/Hint               : Sony
Duration                    : 50s 117ms
Bit rate mode               : Constant
Bit rate                    : 24.4 Mbps
Encoded bit rate            : 28.8 Mbps
Width                       : 720 pixels
Height                      : 480 pixels
Display aspect ratio        : 4:3
Original display aspect rat : 4:3
Frame rate mode             : Constant
Frame rate                  : 29.970 fps
Standard                    : NTSC
Color space                 : YUV
Chroma subsampling          : 4:1:1
Bit depth                   : 8 bits
Scan type                   : Interlaced
Scan order                  : Bottom Field First
Compression mode            : Lossy
Bits/(Pixel*Frame)          : 2.357
Time code of first frame    : 00:00:46;05
Time code source            : Subcode time code
Stream size                 : 172 MiB (95%)

EDIT: Well, I think I might have found the reason. After downloading vcswap and opening up the configuration dialog for Cedocida there is no option for YV411 in the Decoder section. Am I interpreting this correctly?


[Attachment 36005 - Click to enlarge]

[poisondeathray]

Your VFW decoder doesn't support 4:1:1. A VFW decoder is used when you use AVISource(). If you're using cedocida it's not an available option . It's probably the best choice when using AVISource() . FFMS2 and L-smash do support 4:1:1 . As for what to use - do some comparisons for your specific scenario. The benefit probably isn't worth the indexing time (and "pollution" as you eloquently put it) in most scenarios for DV

[jagabo]

I don't think there's any VFW DV decoder that supports any form of YUV 4:1:1 output.

[SameSelf]

pdr and jagabo, I think I agree with you both that no VfW DV decoders output YUV 4:1:1. Trouble is, testing is just that. Maybe stuff works, maybe it doesn't. I downloaded most major VfW DV AVI decoders: Cedocida, Canopus, Avid, GV (did I miss any?). None output 4:1:1, if they even load the clip at all. So, I moved on FFMS2 and L-SMASH.

FFMS2 is very buggy as well. v2.22 that the Avisynth wiki links to here decodes my video green and upside down. When I roll back to v2.21, the green and flip go away, but the output is YUY2 (or was it YV12?), sigh. I ended up having to download a build posted on doom9 here. This appears to work i.e. properly decoded video (no green or flip) and YUV411 output.

Also, VirtualDub doesn't play nice with L-SMASH or FFMS2. I had to switch over to AvsPmod for testing which is better anyway, so I guess it was inevitable. But the initial problems led me to believe L-SMASH wasn't working either. It wasn't until I removed vdub from the chain and did a test encode in ffmpeg that I realized that L-SMASH does indeed work. The same problems occur with FFMS2. If there is configuration that I am missing in vdub, I am interested in knowing.

Bottomline, I have two methods to output YUV411 video now. All this testing has given me a bunch of different ideas and added tremendously to my understanding of video. I can't say with 100% certainty that decoding video with indexing as YUV411 will be better than AviSource() with a VfW DV decoder. But the real fun is about to begin. As for drive "pollution," that's what batch files are for, amiright?