HDMI output from laptop is blurry on USB output TVS

Hi,

I have an Atem Television Studio with the latest 6.1 firmware, and a Dell E6520 with an Nvidia NVS 4200m with HDMI output.
I configured everything to operate in 1080i50 and when hooking my computer up to the Atem TVS and looking at the PROGRAM output on a HDMI television, everything looks sharp and crisp.

But when I run Blackmagic Media Express and record the MP4 stream, the image of my computer screen is blurry (at least the fonts are).

I have some images to demonstrate what I mean:

Here is a still frame in TGA format I grabbed with the Media Express software:


And this is the PNG representation, just to show you what I mean with "blurry":


I have tried all settings on my Nvidia control panel, like changing the digital color format from RGB to YCbCr444, but nothing will improve the "sharpness" of the image that is output from the USB-port on the TVS.

Here is a small capture I did with Media Player Classic, where you can see that the text on the left side of the screen is hardly readable:



Can someone explain why this is happening and if this is normal when capturing mp4 video on the USB output, or am I missing a setting somewhere?

PS: the images are scaled on this forum, in Google Chrome you can right-click the image and choose: open image in new tab, so you can view the full 1920x1080 pixel version.

Well MP4 is by it's very nature (highly) compressed so it will definitely not be the same as when viewing the uncompressed live signal on a monitor. What compression option did you use for the recording?

You might want to check out MXLight- as that actually allows you to configure higher quality (less compression) recordings via H.264 on the TVS than is possible using Media Express.

EDIT: Oh and by the way - it has nothing to do with settings on your Dell. If the video you see live from the program out of the TVS looks good - then that is what your Dell is giving out and you don't need to change a thing there.

With MXlight I get the same results.

I wonder if these people then all used an additional HDMI capture card to record the stream:

youtube.com/watch?v=YySaUoYAAkw at 4'30''
youtube.com/watch?v=S2uLDuryN0s at 8'00''
youtube.com/watch?v=XQ0gOKlkqSg at 2'14''

PS: I am sorry I am not allowed to post URL's, so please put the H T T P S : / / in front of the URLs.

I just want to know if other people experience the same issues like I have on the USB output of the Television Studio?

Did you try changing the bit rate via MXLight up to the maximum?

ALSO Please do answer the question of what bit rate you selected.

And.. I would highly recommend that you do go for an alternative method of captuuring (e.g. Hyperdeck Studio/Shuttle or some other hard drive recorder)

Yes, I have tried all (higher) bitrates in MxLight (up to 30 mbit/s) and Media Express (up to 20 mbit/s), but the problem with the blurred image stays.

I will try to hook up a Mac mini next week and look if it differs.

But I want to know if other people experience the same issue, and if yes, why does it happen?
Because the image from my Sony HVR-Z5E camcorder is superb, even when recording from the USB outputs!

I promise - you will see no difference when you connect a Mac mini up. After all you say "everything is sharp" when you look at the live Program Out. How could it be any different? The H.264 hardware encoder is dealing with the program out. When you connect a Mac Mini up - and it looks sharp (just as the DELL) how will it be any different?

Also Comparing a laptop screen capture - to the output from a camera is not a valid comparison either.

It's definitely related to the compression.

If you had a hard drive recorder - or you used an HDMI / SDI capture card you will not see the same issue.

OK, I've investigated my issue a little bit further.
It seems it has something to do with the interlaced output from the HDMI output on my laptop.
When I set the Blackmagic ATEM to 1080i50 then the laptop image will get "unsharp".
But when I set everything to 720p25 then the image is very sharp and crisp!

But unfortunately I cannot work in 720p mode because:
- I have 2 Sony Z5 camera's and they only output 1080i50
- I need to stream at 1080i50 because I produce Computer Based Training video's and need the higher resolution

I have a Dell E6520 with HDMI out and I also have a Mac Mini with a HDMI output, both images stay unsharp when I connect them to the Blackmagic ATEM and configure them at 1080i50.

My question now is:
How will I get a sharp image from my laptop at 1080i50 when doing a live event with the Blackmagic ATEM?
For example: will the Intensity shuttle pro improve my image?

Two things:

1. The H.264 encoder in the ATEM TVS is known to have an interlace bug, meaning it drops half the fields when encoding, hence your blurry video.

2. To fix this, use MXLight, but click on the Reset Encoder button (I think it's Reset), close MXLight, re-open MXLight, and then capture or stream. That fixes the interlace issue.

2. To fix this, use MXLight, but click on the Reset Encoder button (I think it's Reset), close MXLight, re-open MXLight, and then capture or stream. That fixes the interlace issue.

I have downloaded the latest version of MxLight, and unfortunately there's no option like "Reset Encoder".
There is an option named "Reset resampler settings to automatically defaults" which I used instead.
But it doesn't improve my image in my final TS recorded file.

I am also having contact with BMD support, and this person stated:

Hi Patrick,

I am not saying that you cannot have a 1080i50 output from a laptop to program out, however when this is de-interlaced and compressed using H.264, the quality can deteriorate due to the nature of the video signal.

As computer outputs are generally large white backgrounds with small thin characters, the run length encoding can cause some quality issues. It identifies the white areas as a repetition and therefore can compress this line. When it reaches a pixel (or two) wide black pixel, which would be a character, it will not compress this. Over the whole frame, the compression will be evident because there are very subtle details in the video signal (text).

If you were to play back a video file from the computer in full screen, I suspect the video would be as good quality as the other inputs. It is just the intricate desktop video.

The program output that was captured in those YouTube videos were captured using a HyperDeck, which does not use H.264 encoding. This means the compression would handle minute details, such as text, a lot better than H.264.

If you capture from the HDMI or SDI program output natively at 1080i50, then the quality of the computer video signal will be high.

I hope this has helped.

So I guess the problem lies in the interlaced signal that is fed to the H264 encoder.
If the H264 was to be fed a PROGRESSIVE signal, my problem would be solved, right?!
Because at 720P I have no issues at all with the internal h264 encoder from the TVS.

So a possible solution would be to connect a Datavideo DAC 70 (http://www.datavideo.info/Converters/DAC-70) HDMI converter to the PROGRAM OUT of the ATEM TVS and convert to HDMI signal from 1080i50 to 1080p50.
Then I can connect a live mp4 encoder (I have a Teradek Cube 255) to the progressive output from the Datavideo DAC 70, and stream live without having these artefacts:


Tip: right click image and choose: open in new tab for original resolution!

Do you think that I am right?
If so, I would buy the Datavideo DAC 70 immediately.

Click on "General", and then, "Restart Streaming Server". Close MXLight, wait 10 seconds, re-open MXLight and try to capture in 1080i.

Hi Mike,

I followed your advise, but the result is still the same.
There's no improvement in the image.

I suppose it's by design when the mp4 encoder gets fed an interlaced image like this.

I have one last option, and that is to convert the interlaced signal from the program out to a progressive signal.
That way I can hookup an external h264 encoder, and this encoder will in turn encode the full frame 1080p50 signal to mp4.

I hope it will work that way.

Just wanted to let you all know that converting the signal from interlaced to progressive will resolve this issue.
I ordered an Atomos Connect AC and enabled "2:2 pulldown removal" to convert from 1080i50 to 1080p25.
A Datavideo DAC 70 will do the trick too.
The image is sharp and crisp now.

Except for one thing: my Teradek Cube 255 shifts the image 6 pixels up, leaving a horizontal bar of 6 pixels heigh at the bottom of the screen!
But this only happens with PROGRESSIVE input, with interlaced video input, my screen is as it should be.

OK, I suspect all of my problems are over when I replace this unit...