Author Topic: Video Ipod Playback Specs (Read 6000 times)

gr8ful · « **on:** October 13, 2005, 12:56:24 pm »

Video formats supported: H.264 video up to 768 Kbps, 320 x 240, 30 frames per sec., Baseline Profile up to Level 1.3 with AAC-LC up to 160 Kbps, 48 KHz, stereo audio in .m4v, .mp4 and .mov file formats; MPEG-4 video up to 2.5 Mbps, 480 x 480, 30 frames per sec., Simple Profile with AAC-LC up to 160 Kbps, 48 KHz, stereo audio in .m4v, .mp4 and .mov file formats

Does anyone know what chipset the Video iPod has that allows it to replay video at 30fps?

I was always under the impression that an iPod was not even close to the Zaurus where processor power was concerned. So is it in software that this performance comes from or is the iPod packing more under the hood than Iâ€™m aware of?

If they have a less powerful chipset that the Zaurus and can playback mpeg-4 at 480x480 and 30fps, why canâ€™t the Z with more horsepower produce 640x480 at 30 fps smoothly?

GadgetGuy · « **Reply #1 on:** October 13, 2005, 01:55:16 pm »

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why canâ€™t the Z with more horsepower produce 640x480 at 30 fps smoothly?
[div align=\"right\"][a href=\"index.php?act=findpost&pid=99212\"][{POST_SNAPBACK}][/a][/div]

Who said it cant? 640x480 works nicely on my Z...

Cresho · « **Reply #2 on:** October 13, 2005, 02:19:22 pm »

no problems here either.

gr8ful · « **Reply #3 on:** October 13, 2005, 02:39:25 pm »

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why canâ€™t the Z with more horsepower produce 640x480 at 30 fps smoothly?
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Who said it cant? 640x480 works nicely on my Z...
[div align=\"right\"][a href=\"index.php?act=findpost&pid=99217\"][{POST_SNAPBACK}][/a][/div]

Is that at 30fps or a lesser fps rate? I've seen some of the threads that have dealt with this issue and always came away with the belief that no one was able to get full screen 640x480 at 30 fps without sound issues or glitches in the video. And that in order to get smooth playback without the aforementioned problems, sacrifices had to be made, such as a lower fps or lower screen resolution.

If 640x480, 30fps playback is possible on the Z hardware its obvious I need to update myself on the latest encoding techniques that are yielding these results. High quality video playback is the last real hurdle in my Zaurus experience. Of course I would love more power, longer battery, integrated wireless, but I can find either solutions or work-arounds for all of these except video playback. There is no substitute for your favorite action movie playing full screen at 30fps, flawless sound and video displaying as smooth as butter.

icruise · « **Reply #4 on:** October 13, 2005, 03:38:01 pm »

You can get very good looking video on the Zaurus, but I don't think it can do anywhere near 30fps at 640 x 480, and I'm not even sure about 320 x 240.

GadgetGuy · « **Reply #5 on:** October 13, 2005, 03:52:03 pm »

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You can get very good looking video on the Zaurus, but I don't think it can do anywhere near 30fps at 640 x 480, and I'm not even sure about 320 x 240.
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See this [a href=\"https://www.oesf.org/forums/index.php?showtopic=15325]https://www.oesf.org/forums/index.php?showtopic=15325[/url]
for a nice 640 x480 ( actually, since it is widescreen, it is 640 x 326) demo clip. I am not exactly sure about what fps it is, but it looks very smooth for me...

icruise · « **Reply #6 on:** October 13, 2005, 04:07:52 pm »

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You can get very good looking video on the Zaurus, but I don't think it can do anywhere near 30fps at 640 x 480, and I'm not even sure about 320 x 240.
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See this [a href=\"https://www.oesf.org/forums/index.php?showtopic=15325]https://www.oesf.org/forums/index.php?showtopic=15325[/url]
for a nice 640 x480 ( actually, since it is widescreen, it is 640 x 326) demo clip. I am not exactly sure about what fps it is, but it looks very smooth for me...
[div align=\"right\"][a href=\"index.php?act=findpost&pid=99229\"][{POST_SNAPBACK}][/a][/div]

I encoded that clip. As I say, it looks good. But I don't think it plays back at 30fps.

gr8ful · « **Reply #7 on:** October 13, 2005, 06:11:37 pm »

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You can get very good looking video on the Zaurus, but I don't think it can do anywhere near 30fps at 640 x 480, and I'm not even sure about 320 x 240.
[div align=\"right\"][{POST_SNAPBACK}][/a][/div]

See this [a href=\"https://www.oesf.org/forums/index.php?showtopic=15325]https://www.oesf.org/forums/index.php?showtopic=15325[/url]
for a nice 640 x480 ( actually, since it is widescreen, it is 640 x 326) demo clip. I am not exactly sure about what fps it is, but it looks very smooth for me...
[div align=\"right\"][a href=\"index.php?act=findpost&pid=99229\"][{POST_SNAPBACK}][/a][/div]
I encoded that clip. As I say, it looks good. But I don't think it plays back at 30fps.
[div align=\"right\"][a href=\"index.php?act=findpost&pid=99233\"][{POST_SNAPBACK}][/a][/div]

I viewed the clip and it does playback smoothly, nicely done. The File Info on the clip displayed by Kino2 says this:

Video
Size: 326x640
Codec: DX50
Bitrate: 511608
FPS: 23.976
Audio
Codec: mad
Rate: 32000
Bitrate: 32000
Channels: 1

Can anyone shed some light on the chipset of the Video iPod and how they are able to produce 30fps. I suspect the hardware is not superior to the Zaurus and that they have highly optimized the software. By the way, is the iPod running a scaled down version of Quicktime? I've found no mention of which player it's using.

It is my belief that the next Zaurus will be more revolutionary rather than the evolutionary products recently released Cxxxx's. I'm banking on a faster PXA270 coupled with the 2700G for true full screen 30fps video. Would not be surprised to see a screen upgrade and possibly integrated wireless (sorry to stray from the topic, techdreaming a bit).

icruise · « **Reply #8 on:** October 13, 2005, 07:58:04 pm »

Keep in mind that just because something is encoded at a particular fps doesn't mean that it is being played back at that fps. Mplayer will dynamically skip frames as needed.

Da_Blitz · « **Reply #9 on:** October 14, 2005, 05:52:45 am »

the video card in the x50v from dell is only clocked at 70mhz and is powerfull enogh for xvid @ 640 * 480 with a 1.5mbps vide stream, the cpu only has to decode audio and take the data from the filesystem and dump it to the video card

video decoding is a parrallel task, cpu's are designed to do things quickly and sequentally, thats why a video card always beats a cpu when it comes to video decoding.

gr8ful · « **Reply #10 on:** October 14, 2005, 10:12:04 am »

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the video card in the x50v from dell is only clocked at 70mhz and is powerfull enogh for xvid @ 640 * 480 with a 1.5mbps vide stream, the cpu only has to decode audio and take the data from the filesystem and dump it to the video card

video decoding is a parrallel task, cpu's are designed to do things quickly and sequentally, thats why a video card always beats a cpu when it comes to video decoding.
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Da_Blitz,

would you happen to know if the battery drain from a PXA270 coupled with the 2700G is significantly more than a lone PXA270 dealing with both audio and video? Since the 2700G is specifically designed to deal with video, I was wondering what are the challenges, other than added cost, that would prevent Sharp from putting it in the next series of Zaurii.

icruise,

Does Mplayer dynamically skip frames to attempt to provide smooth playback? How can one determine fps at time of playback?

icruise · « **Reply #11 on:** October 14, 2005, 12:50:49 pm »

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icruise,

Does Mplayer dynamically skip frames to attempt to provide smooth playback? How can one determine fps at time of playback?
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Yes it is to smooth playback, but I'm not sure how you can display the fps (or if it's possible). There are options for controlling the type of frame dropping it does, and you can set it to "none" if you like, but I've found that will result in audio problems.

eji · « **Reply #12 on:** October 14, 2005, 04:43:57 pm »

iCruise, I don't know exactly what you did to encode that clip, but I've tried 1,001 different ways over the past few days (with Simpsons episodes) and I keep coming up with stuttering video and poorly synched audio. Your clip plays beautifully on my stock 6000 (running Zplayer/mplayer) but anything I try encoding is barely acceptable.

What are people using on the Mac? I've tried FFmpeg, Handbrake and D-Vision, all with the same results. The best options so far have been: 400kbps MP4 (Divx 4), 20fps, 48kbps MP3 mono audio, 512x382.

icruise · « **Reply #13 on:** October 14, 2005, 05:42:20 pm »

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iCruise, I don't know exactly what you did to encode that clip, but I've tried 1,001 different ways over the past few days (with Simpsons episodes) and I keep coming up with stuttering video and poorly synched audio. Your clip plays beautifully on my stock 6000 (running Zplayer/mplayer) but anything I try encoding is barely acceptable.

What are people using on the Mac? I've tried FFmpeg, Handbrake and D-Vision, all with the same results. The best options so far have been: 400kbps MP4 (Divx 4), 20fps, 48kbps MP3 mono audio, 512x382.
[div align=\"right\"][a href=\"index.php?act=findpost&pid=99413\"][{POST_SNAPBACK}][/a][/div]

I used PocketDivxEncoder, which is a free program for windows designed for encoding divx for playback on PDAs.

The most important thing seems to be to rotate the video 90 degrees clockwise. It seems that the "true" orientation of the Zaurus is actually vertical and not horizontal. (I'm not sure about the 6000 for sure, but since my clip plays back well on your machine, I guess it's the same). Also, if you're using non-widescreen clips, you probably won't be able to use a width of 640, since the additional information at the top and bottom of the screen (compared to widescreen) will take more processing power to display. But I haven't done much work with fullscreen video on the Zaurus, so I'm not sure.

My Windows desktop is faster than my PowerBook and I don't use it for work, so it's usually free for encoding. So I don't really know about Mac encoding options for the Zaurus, although I've used the programs you mention for other things.

I've ordered a video iPod, so now I'm experimenting with encoding options for that.

Da_Blitz · « **Reply #14 on:** October 15, 2005, 06:04:09 am »

thats the funny thing about the 2700g, at maximum speed (624mhz) the pxa270 drains power like a ***** but the 2700g drains next to no power even when fully active, and as it does all the work you can clock the cpu back to 208mhz meaning 4 hours or more of moives.

to test it out try compiling the kernel on your zaurus while not connected and see how long it lasts (overclocked to 624mhz of course)

in short when watching moives/playing games/accelerating x with xgl (open gl es profile) you would save power by using the 2700g, thats why i want one so badly in my c3k

in terms of how difficult it is to add, well its actually quite easy, however it does drive up the price and would add about $50 aprox in hardware to the chip. i think it was mainly a cost thing but there is also not alot of room even if you use the chip with built in RAM (16MB can use up to 32MB in total), its quite easy for us to add but intel dosent like small volume sales

the main problem would probely be the amount of time it would take to implment and test it. but driver support would be another, i dont think sharp would like to write a driver and if they did i would think the quality of it would be farily poor as they are using the montavista linux kernel there would be no driver support from the vendor, it seems they wanted somthing that was plug and play without much fiddling otherwise they could have rolled thier own kernel/distro

i guess its up to us

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Author Topic: Video Ipod Playback Specs (Read 6000 times)