Huffyuv & colour spaces

[VideoFanatic]

My 720 x 480i videos are YV12. I'm using Huffyuv because some Avisynth filters only work in VirtualDub so I make a lossless file. Then I convert the lossless file to h264.

Does Huffyuv only output RGB32?

Is there any reason why I should NOT keep my video in RGB32. The videos will end up as 720 x 480i on a Bluray disc for viewing on my TV.

[themaster1]

huffyuv record / output in yuy2 by default
You should record your video in Yuv imo, yv12 or yuy2

[VideoFanatic]

I installed Huffyuv and it outputs RGB by default. MediaInfo says the AVI is RGB.

[jagabo]

I installed Huffyuv and it outputs RGB by default. MediaInfo says the AVI is RGB.

That doesn't mean anything. Use an AviSynth script:

AviSource("Huffyuv.avk")
Info()

To see what it outputs. It's usually YUY2. Unless you have the "Always suggest RGB format for output" option enabled. Or encoded in RGB mode.

[VideoFanatic]

My video is YV12. So do I just load my MPEG2 script as normal into VirtualDub but add the Info() line and it will say what colour space the video will be output in, is that correct? It says YV12. Or does that just tell you what colour space your video is already before you output?

After the lossless file is created I used MediaInfo on the AVI and it says it's RGB which I don't understand? The only thing in my script was RemoveSpotsMC(last, 0).

I don't have "Always suggest RGB format for output" enabled.

[themaster1]

have you used directshowsource to load your mpeg2 or mpeg2source ?

[VideoFanatic]

MPEG2source

[poisondeathray]

Sometimes mediainfo is wrong. Open the exported AVI up with AVISource() and use Info()

Are you using any vdub filters ? or are you using video=>fast recompress (this will prevent any colorspace conversions)

My video is YV12. So do I just load my MPEG2 script as normal into VirtualDub but add the Info() line and it will say what colour space the video will be output in, is that correct? It says YV12. Or does that just tell you what colour space your video is already before you output?

Yes, info just tells you what the input is, or everything upto the info() line . You might have done something in vdub to cause the problem

[jagabo]

Info() tells you information about the video at the point in the script you invoke it. So

AviSource()
Info()
ConvertToYV12()

will tell you what colorspace (as well as a lot of other stuff) AviSource() delivered. If Huffyuv encoded it should report YUY2 (with the caveats mentioned earlier).

AviSource()
ConvertToYV12()
Info()

will tell you the video is YV12 -- because you converted it to YV12.

[VideoFanatic]

OK my source video is YV12. I loaded the following script into VirtualDub and it said the video is YV12.

setmtmode(5,9)  
Mpeg2Source("X:\Video with Comets.d2v", CPU=6)
setmtmode(2)

RemoveSpotsMC(last, 0)  RemoveSpotsMC(last, 0)  

Separatefields() RemoveSpotsMC(last, 0)  RemoveSpotsMC(last, 0)  RemoveSpotsMC(last, 0) Weave()

Info()

After I saved an AVI with the default Huffyuv settings I loaded the AVI with the following script:

AviSource("X:Video with Comets after Huffyuv.avi")
Info()

It said the video is RGB32. What I was concerned about is that whenever you convert a colour space to another you lose a little picture quality. Some filters require YV12. So in my future Huffyuv scripts I will be converting from RGB32 (what Huffyuv encodes as by default) to YV12. Will I actually lose picture quality since it's making a lossless video?

[jagabo]

As I said earlier, make sure the "Always suggest RGB format for output" option is NOT enabled. Make sure you didn't do anything in VirtualDub (in your first compression from AviSynth to Huffyuv) that caused the video to be converted to RGB. Generally, that means no filtering in VirtualDub and make sure VirtualDub output color depth isn't forced to RGB (Video -> Color Depth).

Huffyuv can't save in YV12. Only YUY2 or RGB. If you want AviSynth to perform the YV12 to YUY2 conversion use ConvertToYUY2(interlaced=true) at the end of your script. If you want VirtualDub to do the conversion use Video -> Color Depth -> Output Format to Compressor/Display -> 4:2:2 YCbCr (YUY2).

[VideoFanatic]

Make sure you didn't do anything in VirtualDub (in your first compression from AviSynth to Huffyuv) that caused the video to be converted to RGB.

Huffyuv can't save in YV12. Only YUY2 or RGB.

The first sentence seems to contradict the 2nd?! If Huffyuv only saves in YUY2 or RGB then how could I do anything to cause it to save in RGB instead of YV12?!

If I just load my source video with a script as simple as this: Info() then save as AVI, then load an identical script with the AVI as the source then it says the video is RGB32 which is to be expected isn't it?

I made sure I unticked "always suggest RGB format for output. I haven't changed any settings in VirtualDub from the defaults.

Can someone clarify this issue for me please: Some filters require YV12. So in my future Huffyuv scripts I will be converting from RGB32 (what Huffyuv encodes as by default) to YV12. When doing a lossy encoding you lose picture quality when converting the colour space so do you still lose quality like that when making a lossless video with Huffyuv?

[jagabo]

HuffYUV does not encode to RGB32 unless it receives RGB32, you have it set to encode as RGB, and you have the Enable RGBA option enabled.. You have some setting in VirtualDub that's causing the conversion to RGB.

[sanlyn]

I suspect VideoFanatic is viewing the script in VirtualDub and saving in "full processing mode". VirtuaLDub will always output RGB unless the user selects YUY2 as "Color depth", set compression to YUY2, and set processing to "fast recompress". Huffyuv compresses only to RGB or YUY2. If you want YV12, use Lagarith.

[jagabo]

I suspect VideoFanatic is viewing the script in VirtualDub and saving in "full processing mode". VirtuaLDub will always output RGB unless the user selects YUY2 as "Color depth", set compression to YUY2, and set processing to "fast recompress". Huffyuv compresses only to RGB or YUY2. If you want YV12, use Lagarith.

VirtualDub doesn't convert to RGB anymore unless you are actively using filters or have specified an RGB color depth. Even in Full Processing mode.

[VideoFanatic]

I'm using Lagarith now as it supports YV12. Most of my scripts use YV12. However the last step in my script does this: ConvertToRGB32(interlaced=true) RGBAdjust(1.0, 1.0, 1.1, 1.0, 0.0, 0.0, 0.0, 0.0, 1.00) Converttoyv12(interlaced=true)

My videos were taped off TV in 720 x 480i. Is there any reason why I can't just keep the conversions as RGB instead of losing quality converting back to YV12 (as shown above). The videos will be muxed to a Bluray sturcture.

[jagabo]

My videos were taped off TV in 720 x 480i. Is there any reason why I can't just keep the conversions as RGB instead of losing quality converting back to YV12 (as shown above).

You can probably leave the video RGB. Unless something you are doing downstream requires YV12. RGB will be bigger. RGB is 3 bytes per pixel, YUY2 is 2 bytes per pixel, YV12 is 1.5 bytes per pixel.

The videos will be muxed to a Bluray sturcture.

Which means they'll end up YV12 in the end.

[VideoFanatic]

Just noticed that. My h264 encoder converts the RGB file into YV12 automatically. Is RGB not compatible with Bluray then?

[sanlyn]

I suspect VideoFanatic is viewing the script in VirtualDub and saving in "full processing mode". VirtuaLDub will always output RGB unless the user selects YUY2 as "Color depth", set compression to YUY2, and set processing to "fast recompress". Huffyuv compresses only to RGB or YUY2. If you want YV12, use Lagarith.

VirtualDub doesn't convert to RGB anymore unless you are actively using filters or have specified an RGB color depth. Even in Full Processing mode.

I thought RGB color depth is on by default, unless you opened VDub and earlier set it to another colorspace, then subsequently opened new file without closing VDub.

[themaster1]

Just noticed that. My h264 encoder converts the RGB file into YV12 automatically. Is RGB not compatible with Bluray then?

The video data stored in blurays and dvd's is Y'CrCb not rgb

[VideoFanatic]

I opened the stream folder of a 720 x 480 Bluray I made and used MediaInfo on a video and it said it was YUV.

[jagabo]

I thought RGB color depth is on by default, unless you opened VDub and earlier set it to another colorspace, then subsequently opened new file without closing VDub.

I've been using VirtualDub for many years so I don't remember what the original defaults were. In any case, on the Color Depth dialog there's a Save As Defaults button. So you can specify what you want as the default every times VirtualDub starts.

[sanlyn]

Well....yes, I'm aware of saving the default setup, but it seems most people use VirtualDub for RGB filters. So if you don't want to save as whatever default colorspace you've set, you still have to change the setting every time you want a different colorspace. My point to VideoFanatic is that he should check whatever default colorspace his VirtualDub installation is using, and change it if or when necessary. When VirtualDub is first installed, it saves to RGB24 by default. If you don't want the RGB default, change it.

[VideoFanatic]

I changed no settings in VirtualDub apart from in Lagarith I set it to output YV12 and it does so.

I don't know if you guys know this but I was getting fed up of VirtualDub not remembering settings when I loaded the program - for example I had to select the compression codec I wanted every time I started the program. To make it remember your settings, do this:



File, Save Processing Settings, save in your VirtualDub plugins folder as whatever you want. Note that your settings won't load automatically. You have to load them manually. To load automatically you can make a shortcut as follows:
Right-click on the "VirtualDub.exe" file and create shortcut. In Properties for the shortcut go to the end of the Target box and type: " /s.\plugins\Lagarith.vcf"

Replace the bold text with whatever you called your settings file. Now whenever you open VirtualDub your settings are loaded automatically.

[sanlyn]

You can change the default output colorspace with:
1. "Video..."
2. "Color depth..."
3. Set the default output color depth you want.
4. Click"Save As default"

Other project settings are saved as .vcf's, as you describe. Many VDub users do this all the time, there's nothing unusual about it. If you want different settings you have to change them, just as you would with almost any other software.

[lordsmurf]

VirtualDub doesn't convert to RGB anymore unless you are actively using filters or have specified an RGB color depth. Even in Full Processing mode.

As of which version?

[jagabo]

VirtualDub doesn't convert to RGB anymore unless you are actively using filters or have specified an RGB color depth. Even in Full Processing mode.

As of which version?

A few years ago. Go to Video -> Color Depth. Set Decompression Format to Autoselect. Set Output Format to Same As Decompression Format.

[sanlyn]

"Same As Decompression Format" is not the installed default for that column.