[General Topics] Menneisyys:
HP iPAQ hx4700:

Note that the “Video” setting dialog also contains a “Video quality” drop-down list. It should never be used because in the “Medium” setting, it severely degrades video quality (it effectively halves (!) the original (!) resolution – that is, VGA source becomes QVGA) and, in “Low” setting, almost noting will be visible. The speed gain its usage results in is pretty low too. Finally, it only has an effect on non-AVC (for example, ASP) source; this is why I’ve added the MQ (“Medium Quality”) remarks in there. (For example, (MQ: 319) with the HTC Universal playing back a 204 kbps VGA movie means 319% benchmark when the video quality is set to Medium.)

Halving the original resolution means that, if you play back a VGA ASP movie on a QVGA device that supports the quality setting, in general, you can give a try to switching to Medium quality – you won’t see much image degradation (as opposed to what you would see on a VGA device). This especially pays off if, otherwise, you couldn’t play back the video without dropped frames.

1.4.5.4 QVGA Pocket PC’s and MS Smartphones

Now, from VGA Pocket PC’s, let’s move to QVGA devices (Pocket PC’s and MS Smartphones alike): the pretty old, WM2003 HP iPAQ 2210 (run by a 400 MHz Intel Xscale PXA-255) and the new, low-speed HTC Vox (s710) MS Smartphone, run by a 200 MHz TI OMAP CPU. (Note that, as far as other TI OMAP-based models are concerned, I’ve also benchmarked the HTC Wizard. I’ll show the results in a later chart.)

HP iPAQ 2210:

HTC Vox / s710:

As can clearly be seen, the 400 MHz iPAQ 2210 is just able to play back QVGA movies without having to resort to manual quality degradation (bilinear prediction / CABAC / deblocking). With the 200 MHz TI OMAP Vox, the situation is far worse – you cannot watch QVGA-width AVC videos on Windows Mobile models based on this CPU without manually decreasing the quality in encoding time (in runtime, just disabling deblocking won’t suffice).

1.4.5.5 Nokia N95

Finally, let’s see how probably the best multimedia smartphone of today, the TI OMAP-based (running at 330 MHz) Nokia N95 (firmware version v20, which is a bit faster at video playback (too) than v12) fares:

As can clearly be seen, it’s just able to play back 640*272 ASP videos without dropped frames – unlike the Vox or anything Windows Mobile based on the TI OMAP platform (without heavy overclocking).

1.4.5.6 Note that…

I haven’t benchmarked any Qualcomm MS7200-based devices because the next, soon-to-be-released, 1.2 version of CorePlayer will have much better support for it. Also, GoForce 4000 / 5500-based devices like the O2 XDA Flame are promised hardware support sometimes next year – see THIS for more info. Therefore, I haven’t tested them either. According to serveral users, both Acer (GoForce 4000) and the Flame (5500) have severe problems with playing back video – as is the case with the Qualcomm MS7200-based devices right now.

The source video I used was a 640*272 / 320*144 one – that is, a traditional 2.39:1 (35 mm anamorphic / Panavision / 'Scope) movie. With, vertically, considerably bigger movies (1.85:1, 16:9 (1.78:1) or even plain 4:3 – see THIS for more info) will result in a somewhat worse results.

For example, with a real 4:3 (640*480, VGA) 550 kbps ASP source, the Nokia N95 benchmarks at about 93%, as opposed to the ~111% of the “thin” 2.39:1 movie resized to 640*272 (keeping the aspect ratio).

1.4.6 Other tweaking

I’ve also thoroughly tested the performance gain using other checkboxes in the already-known (it’s there that you need to disable deblocking) Advanced tab of CorePlayer. Note that the test video was a fast one (the Standard - AVC 640-wide one was 1995 kbps, the Standard 320-wide one was 1468 kbps etc.); with much lower (and, therefore, much more recommended) bitrates (between 80…450 kbps, depending on the resolution), the absolute numbers would have been considerably higher, while the relative rations would have stayed approximately the same.

As can clearly be seen, trying to increase the performance with the other, Advanced checkboxes are pretty much futile. As a rule of thumb, it’s only the three parameters (Deblocking both runtime and encoding time and CABAC / Bidirectional Prediction at encoding time) that you should pay attention to. Also note that, by default, CorePlayer defaults to the best and most effective playback method (video output). It’s only with some ATI-based devices that you MAY want to override its decisions, should you encounter for example the infamous greenish effect.