Examples of the Pixelation Seeing on VOOM after Encoding Upgrade

[Sean Mota]

A lot of users have posted or described the PQ problems we are currently seeing of VOOM after the Harmonic Encoder upgrade was done. I thought it would be good to posts pictures of these problems. I am posting some pictures to illustrate my points. First, I am taking these pictures off my Sony GWII. My stb is set at 720p and using DVI. The native resolution of the TV is 768p.

Methodology: I recorded a segment of Monsters HD. I recorded this to my HS2 Panasonic DVD recorder through composite of the Motorola STB (VOOM) and input to the HS2 composite input. My HS2 is connected through component to my TV. The HS2 upscales to 480p and then the TV upscales that to 768p.

I know what you will say a lot of scaling up/down but I checked back to the image I saw in the DVI input and the DVD recorded the artifact of what I want to explain.


Frame Fading/cutting Artifacts (Blockiness - seen during dissolves and fades) Whenever a still or moving picture cuts to another frame as it is fading the picture pixelates and one can clearly see the macro blocking in the picture.

The picture posted is from a Monster HD frame. I tried to take frame by frame as much as could to capture each frame. These are not second by second frames. I skipped some but I believe it illustrates the microblocking artifact at the end of the frame. Understand that this a poors man design to illustrate the point and that the upscaling/downscaling process can insert its own artifacts as well.

The last pictures becomes very blocky as it finishes the fading and the new frame replaces it. Also as the fade is happening there is lots of grain (best word I can use to describe it) that the picture does not reveal.

If you would like to comment on these, please comment on this thread: http://www.satelliteguys.us/showthread.php?t=55293

I am going to try to posts some other examples.


NOTE: This in no way represents a way to bad mouth VOOM at all. I thought that their PQ before the Harmonic Upgrade was excellent or acceptable to what I saw in other providers. I understand that Voom is still tweaking their encoders and this is no critism but feedback of what a lot of us are seeing to help them tweak the encoders.

I appreciate all the communication with the Voom Engineers are doing with the forum and with personally to correct this PQ problem. Some of you have contacted me with previous experience in given feedback to engineers to correct problems like this. I have the names and information of those that are willing to give them immediate feedback. So if this is needed we have a good amount of people that are willing to put sometime on this as well.

 

[Sean Mota]

Flashing Lights Pixelation. These I took from Monsters HD using the same methods. This is good graphic which happens to be part of the same graphics I took above. This one flashes lights on a billboard. The flahes pixelated a lot and the macro blocking were obvious.


I am not advocating that VOOM is like this all the time. I am taking frames that are very subscetiple to artifacts. If the picture does not contain flashing lights, it looks pretty darn good but when the flashing lights do happen, the problem is there.

 

[Sean Mota]

MPEG Files

These are two MPEG files which show the graphics that it is showing on Monsters HD today and from which I took the pictures. These are less than 5 seconds long and you will not be able to see these artifacts on it but the VOOMERS can check those graphics on Monsters HD.

Download those graphics to your PCs and play them from there rather than the server. I hope they do not take the server down.


I put the extension JPG. When you download them, change the extension to MPG to play them.

 

[Sean Mota]

While watching WorldSport today, I could see that the picture was much better than last Tuesday. The motion artifacts are not there but there are two problems that I saw which I cannot take pictures because it will very hard to capture the effects.

Scan Lines Whenever the camera focused on a player on the field, the background looking blurry (as expected since the camera is on the player), exhibit scan lines. In order to see them, you need to look at spot where you are not looking at the fans background. I thought for a minute that it was due to my LCD Rear Projection but I went to my other room and was able to verified that the scan lines were on the DLP as well.


Note: not sure about the Scan Lines. I saw the skating program on WorldSport this afternoon and did not see the scan lines. Could it be a production matter? I do not know.

Compression Field Picture (Wavy Noise - seen during pans) this happens with the camera field. The camera follows the football and the players. If there's no motion, the field, the players and the fans look perfect. But if there's motion, The compression from the field occurs. It is hard to describe but as one follows the ball and the players, the green background of the grass, looks like it is moving with the players and the ball. This almost looks like the Fox dancing grass effect on the Football games this year but not as pronounced.