What do you think about these performances?

Hello all.
My new HTPC is finished and everything is tuned. The system is:

- AMD 4850e 2.6Ghz
- Motherboard Gigabyte with HDMI and s-video output
- Onboard ATI Radeon X1250
- Onboard audio 5.1
- 1GB RAM
- HD 160GB 7200rpm
- XP Pro SP2 with only minimum services started, no antivirus, no firewall, nothing else that could slow down the cpu. It boots in few seconds. Latest drivers for graphic (catalyst), audio, system etc.

The pc is connected to a standard crt tv through s-video port and to a stereo ampli through rca cable.

XBMC configuration:

Resolution 720x576 60HZ (same as desktop)
VSync always ON
Hard disk cache 4096kb
Upscaling method Sinc
Audio stereo

I could be more precise when I will be in front of the pc, now am I at work.

I want to play only sd contents from internal hard disk. All my video files have resolutions like 700x400, 680x340 and similar, which I expected to be rather simple to handle. They are xvid, divx and video_ts dvd folders.

Here are my thoughts about perfomance: the movies are played at a sufficient speed and one can look at the show without much pain, but they are never *smooth* and this doesn't help the immersion into the show. The main symptoms are:

- Sometimes the image is somehow "floating", even during scenes with few movements
- Panning are definitely not ok
- Sometimes the movie suffer of a "stop and go" effect, very very short but visible.

I supposed my 4850e (which has 2 core running at 2.6Ghz) to have better performances on sd content, expecially on those file with low resolution, such as 680x340 or similar
I have not tried playing the same files with other player but I am rather sure that they would play smoothly.

I know that much work is currently being done in order to make xbmc able to deliver a smooth playing, but I thought that this only applies to hd contents.

What are your impression about this results? Do anyone have a similar system with different performances?

Try turning off the High Quality Upscaling (or switch to Lanczos or Bicubic as Sinc is the most power hungry) and see what it's like.

Hitcher Wrote:Try turning off the High Quality Upscaling (or switch to Lanczos or Bicubic as Sinc is the most power hungry) and see what it's like.

I have done some measurements, here are the results.

- With High Quality Upscaling always on and Sinc method, the average usage of cpu is about 17-20%, with peak about 25%, and frames are quite stable on 25fps. With this configuration the playing suffers of those symptoms I described.

- With High Quality Upscaling always off, the average usage decreases to 7% with peak about 10%. Frame are still stable on 25fps. With this configuration the playing seems better. Bad symptoms are harder to see, but not totally disappeared, while horizontal rows are still very visible from time to time, expecially during panning and fast movements. I remember that I am talking about 680x340 divx movies.

What I don't understand is why an average cpu usage of only 25% should slow down the playing in such a visible way. 25% means that cpu still has 3/4 of its power ready to be delivered


I also did some testing with vsync option and there are the results:

- With Vsync always off, the playing appears to be more fluid and "reactive" (I think that reactive is the appropriatest word to describe it), frames are stable on 25fps. Unfortunately it seems that horizontal rows are heavier and more frequent.

- With Vsync on, the video seems to suffer the horizontal rows a bit less, but it really seems less reactive. Frames are STILL stable on 25fps but, it's not simply to explain, playing seems slower and not so reactive.


Making a long story short, I have the impression that numbers (usage, fps etc.) are ok with all configuration I tested, but smoothness is never really reached.
For now I leave High Quality Upscaling always off and Vsync always off and I'll see how the life will be. Of course I will appreciate any feedback.

Try turning VSync 'ON' for your video card and 'Let driver decide' in XBMC (needs a restart).

Also I think you need to be looking at the AQ (Audio Queue) and VQ (Video Queue) figures not just the CPU.

Hitcher Wrote:Also I think you need to be looking at the AQ (Audio Queue) and VQ (Video Queue) figures not just the CPU.

Just checked, here it is the complete log of a 608x336 xvid movie with mp3 audio at 48000khz, 165kb VBR:

- AQ 99% cpu 3%
- VQ 30% cpu 3%
- FPS 25 stable
- CPU average usage about 10% (which becomes 25% with high quality upscaling Sinc)

What does those AQ and VQ mean? And that 99%? :confused2:

Hitcher Wrote:Try turning VSync 'ON' for your video card and 'Let driver decide' in XBMC (needs a restart).

Also checked this and it seems better! It also really depends on the file (event at same file resolution), with many movies there are visibile improvements in smoothness, in other movies not so much and horizontal rows still appear. Anyway now it seems a better configuration.
I have activated triple buffering too. Not sure anyway if this helps.

what you are seeing are most likely interlacing artifacts.

uchenzei Wrote:What does those AQ and VQ mean? And that 99%? :confused2:

Not 100% sure on this but I think the higher the percentage the better and they're the audio and video queues.

spiff Wrote:what you are seeing are most likely interlacing artifacts.

and is it possible to avoid or reduce them?

In the OSD when playing a video you can turn it off.

Hitcher Wrote:In the OSD when playing a video you can turn it off.

Ok, I have never tried that menu voice, so now I'll give it a try and test the various options (I see Bob, auto and more, but online manual refers to different ones, xbmc ones?, so it's time for empiric method)

Probably is a strange question for many, but from where could I see whether a file is interlaced or not?