how to screen capture with uncompressed video?

[uglijimus]

I am currently using OBS to capture my desktop for very short tutorials. I like it, but I want better if possible.
I want to screen capture with uncompressed video even though I know it will result in huge files. I am only screen capturing
30 seconds at a time and I will compress them to something suitable for Davinici Resolve which I am currently using as my video editor.

I don't want lossless compression because I have tried Lagarith and other lossless codecs and wasn't that impressed. I am looking for something
that makes it near impossible to tell the recorded video from actually looking at a desktop in real time if it all possible, and I am thinking that
uncompressed video is the way to go.

p.s. I tried virtual dub and couldn't get it to work and neither could I do it with FRAPS for whatever reason.

thanks!

[jagabo]

I don't want lossless compression because I have tried Lagarith and other lossless codecs and wasn't that impressed.

Then you did something wrong. Lossless compression is exactly what it says -- lossless. In all likelihood you performed a colorspace conversion. Since you are capturing the screen you are capturing RGB, set Lagarith (and whatever software you're using) to RGB or RGBA mode, whichever is suitable.

If you want to capture a large desktop without compression you will need to use a striped RAID array or an SSD. Hard drives' sustained write rate is too low for, say, uncompressed 1920x1080 RGB or RGBA.

[uglijimus]

I don't want lossless compression because I have tried Lagarith and other lossless codecs and wasn't that impressed.

Then you did something wrong. Lossless compression is exactly what it says -- lossless. In all likelihood you performed a colorspace conversion. Since you are capturing the screen you are capturing RGB, set Lagarith (and whatever software you're using) to RGB or RGBA mode, whichever is suitable.

If you want to capture a large desktop without compression you will need to use a striped RAID array or an SSD. Hard drives' sustained write rate is too low for, say, uncompressed 1920x1080 RGB or RGBA.

that may be true regarding Lagarith, but it's not like it was at 50% of the original quality, more like 90% so very close.

I looked up striped RAID and it's greek to me. Is there a software that uses this where I can screen capture with uncompressed video?

[raffriff42]

The loss you see is probably the conversion from RGB to YUV 4:2:0, which makes color details look soft -- either that or the conversion itself may cause incorrect colors. Capture with an RGB codec. AFAIK OBS always records YUV 4:2:0. You need some other software such as Fraps or DXtory. Fraps is much easier to use, but Dxtory supports a pseudo RAID called "Distribution Writing." It requires a merge operation before you can edit the video. IIRC Dxtory also supports uncompressed, but the data rate is so high, I/O throughput can become an issue; stick with RGB lossless.

[jagabo]

that may be true regarding Lagarith, but it's not like it was at 50% of the original quality, more like 90% so very close.

Lossless doesn't mean 90 percent. It literally means lossless. The picture that comes out of the Lagarith decompressor is the exactly same as the picture that went into the encoder. If you see a difference it is not Lagarith's fault but something else in your processing.

Is there a software that uses this where I can screen capture with uncompressed video?

Sorry, I don't keep up with screen capture programs. I use OBS or VirtualDub on the rare occasion I need screen capture. OBS doesdn't support lossless capture. VirtualDub does but I haven't been able to get it to capture high frame rates without dropping and duplicating frames. But once again, if you want to record uncompressed high definition video you will run into hardware bottlenecks. 1920x1080, 24 bit RGB at 30 frames per second is 186 MB/s. That's pretty much the limit of what modern hard drives can sustain -- but only at the fastest part of the drive, the outer cylinders. The slower parts of the drive, the inner cylinders, are typically about 1/3 that speed. Don't be fooled by the advertised "SATA 6 Gb/s". That is the rate at which bits pass over the SATA interface. The rate at which data is read off, or written to, the platters is much less.

[uglijimus]

The loss you see is probably the conversion from RGB to YUV 4:2:0, which makes color details look soft -- either that or the conversion itself may cause incorrect colors. Capture with an RGB codec. AFAIK OBS always records YUV 4:2:0. You need some other software such as Fraps or DXtory. Fraps is much easier to use, but Dxtory supports a pseudo RAID called "Distribution Writing." It requires a merge operation before you can edit the video. IIRC Dxtory also supports uncompressed, but the data rate is so high, I/O throughput can become an issue; stick with RGB lossless.

i tried both dxtory and fraps on both of my computers (desktop and laptop) and pressing the hotkey button to record does nothing. Does it have to be a game? that can't be right is it??

[poisondeathray]

What application did you use to record lagarith? Was it set to RGB mode ?

How did you "view" the recording? Not all media players or applications playback RGB files as RGB . Some have a YUV422 intermediate pathway



What is the "90% quality issue" specifically ? Can you describe what is going on ? Is it the blurred color edges on things like thin text or graphic edges ? I'm wondering if there is something else going on.... like a decoding issue.

99.999% of the time, the final distribution format will be 4:2:0 subsampled anyway. You're not going to be uploading RGB or lossless tutorials for viewers.

Another issue is compatibility. Resolve is very picky as to what it will accept. You might have to take another conversion step to convince resolve to behave



But you can use the old free camstudio to record in RGB, or camtasia. If you select lagarith make sure you are in RGB mode. Some desktop recorders do not record RGB, they actually have a 4:2:2 or 4:2:0 step in between . This deterioration can be seen when looking closely at color edges

Or ffmpeg can record desktop, or with gdigrab and you have many codec options . (But gdigrab is slow , high cpu usage and unoptimized, but a lower framerate might be ok for tutorials) .

[raffriff42]

>Does it have to be a game? that can't be right is it??

My apologies, yes I was thinking of game capture. For capturing a tutorial, you might try Virtualdub Filtermod, with an RGB codec of course -- I did a quick test and it seems to work:

(compression dialog )

[Attachment 44472 - Click to enlarge]

(sample result)

[Attachment 44473 - Click to enlarge]

Personally I use VMWare Workstation movie capture for tutorials, as it can capture everything - even the boot screen!

[pandy]

that may be true regarding Lagarith, but it's not like it was at 50% of the original quality, more like 90% so very close.

Why you think so? Please provide samples (simple picture will be sufficient) - lossless is lossless even if file size is smaller.

[uglijimus]

ok, a bit of an update. I found a lossless setting on the simple settings of OBS. It results in huge files, which is ok, because then I use supersimple converter to encode them to a AVI jpeg format which Davinici seems to like and I am happy with the quality.

However, I am not done experimenting. I am going to download camstudio and record in RGB and also try out VMWare Workstation as well.

as far as the 90% comment...Years ago when I was working with the lagarith codec, I would video capture my desktop, save the video, play the video and minimize and look at my desktop vs. the recorded desktop. I would A/B it trying to get it to the point where I couldn't tell the difference which never happened. But as poison death ray said, it may be because the video player may not have the capacity to play back the RGB files correctly. I may have never given it a fair chance.

basically it seemed to have a slight haze to it and the letters of the files on the desktop were softened, losing the crispness of the original.
I will experiment later and come back here to tell of my results of camstudio(RGB) and VMWare Workstation.

thanks everyone

[jagabo]

Years ago when I was working with the lagarith... it seemed to have a slight haze to it and the letters of the files on the desktop were softened

That's almost certainly an RGB to YUY2 or YV12 conversion.

https://forum.videohelp.com/threads/319360-DVD-LAB-PRO-color-map#post1977264

You didn't use RGB mode in lagarith, or you converted before encoding with Lagarith.

[uglijimus]

Results of my experiment:

Virtual Mod- I recorded something, hopefully my screen, but I could not play it back even though under the properties it is listed as an AVI file. I could not encode it either. it failed and crashed when I put it in SuperSimple Video Converter.

VMWare Workstation- I could not install it, because it said that my computer was missing some kind of spec in order to install.

Lagarith with Camstudio. As poisondeathray and jagabo have suggested, the video player I was using, did not display the capture video using Lagarith in the most honest light. After using the settings that jagabo had shown, I got a practically perfect picture. At one point, I couldn't tell difference between the recorded video I was looking at and my desktop in real time! when I uploaded it to YT it was fantastic. and this is what I wanted the whole time. But of course there is a problem...

so the other day, you may remember, I found a lossless codec for OBS. I used this to capture my desktop (huge file) and then encoded it with SuperSimple Video Converter to an avi j-mpeg format that works really nicely with Davinci Resolve (meaning the playback is very smooth when editing the file). I even rendered the file with Davinci, uploaded to YT and was pretty happy with it.

I tried the same thing with the Lagarith file. I put it in SuperSimple Video Converter to the same avi j-mpeg format I used for the OBS lossless codec which appeared fine when playing it back through a video player. BUT, when I put it in Davinici Resolve, I get a "media offline" error. It recognizes the file, but will not display the picture. There is only a "media offline" red screen replacing the original video.

I can live with OBS lossless codec--->supersimple video converter--->DaVinci, but after seeing what Lagarith is capable of, I would LOVE to get it to work somehow in Davinci.
These are my options:

1. live with the OBS lossless code and forget lagarith
2. try other encoding options in SuperSimple Video Converter to get the Lagarith recorded file to a.) not display the "media offline" error in Davinci b.) and have smooth playback when jumping around within the file while in Davinci
3. try a different Video encoder that will encode the Lagarith file to satisfy a.) not display the "media offline" error in Davinci b.) and have smooth playback when jumping around within the file while in Davinci. Something tells me that SuperSimple Video Converter, when encoding, is somehow leaving a portion of the original file's "content" in tact or something which is why Davinici is rejecting the Lagarith file and not the OBS lossless file despite being encoded by the exact same process.
4. go to the Black magic forum and ask if anyone else has had a similar issue with Lagarith in Davinici.

any recommendations on a different video encoder? or any other suggestions?