PocketTV Team

Originally Posted by Dad

WOW! 1MB, thats pretty extreme compression :D

Well, DVD, which are compressed in 720x480 (slightly larger than VGA) in MPEG-2 format (about the same compression efficiency as MPEG-1, for the same resolution), take usually about 5GB to 7 GB, if I'm correct. So 1GB is not that bad for VGA resolution. The source, uncompressed video would occupy 50 to 100 GB.

Using DivX (MPEG-4) you might be able to get 90 min of VGA resolution in 500MB, but the quality will probably be lower. I think that you still need about 600-700 MB to get quality equivalent to 1 GB with MPEG-1. DivX will save you about 30-40%, granted. Have you tried encoding VGA res in less than 1 Mbit/sec with Divx ?

Dad

Originally Posted by PocketTV Team

Well, DVD, which are compressed in 720x480 (slightly larger than VGA) in MPEG-2 format (about the same compression efficiency as MPEG-1, for the same resolution), take usually about 5MB to 7 MB, if I'm correct. So 1MB is not that bad for VGA resolution. Using DivX (MPEG-4) you might be able to get 90 min of VGA resolution in 500KB, but the quality will probably be a bit less. I think that you still need about 600-700 KB to get quality equivalent to 1 MB with MPEG-1. DivX will save you about 30-40%, granted.

Are we getting MBs GBs KBs Kbs and Mbs a bit mixed up here ?

PocketTV Team

Originally Posted by Dad

Are we getting MBs GBs KBs Kbs and Mbs a bit mixed up here ?

Oppps, yes, the previous posts have been corrected (this one too!). I need to hike my dose of caffeine, evidently!

KB, MB etc are file size in Kilo-byte, Mega-byte (for a 90 min file). Mbps = Megabit per secong is the encoding bitrate, i.e. number of BITS per second of video.

at 1.7 Mbit/sec, 90 minute video = 5400 seconds, so it will take 5400 * 1,700,000,000 bits = 9,180,000,000 bits = 1,147,500.000 bytes = about 1 GB.

You can easiely do the math for other bitrates and durations.

Just remember than 1 Mbps = 1,000,000 bits per second, while 1MB = 1024*1024 = 1,048,576 bytes and 1GB = 1024 MB :) oh, and there is (usually) 8 BITS in a byte.

flipcody

Pockettv team:

I just did a hard reset, installed only pockettv 1.0.3, and still got only 150.25%.

Weird that there would be such a difference between roms. Betaplayer (.096) actually picked up performance from A01 to A02 rom. As you said it really doesn't matter at that speed but if you are claiming that it is running at 187% it would be nice to resolve.

__________________
Dell Axim X50v
Kingston 512mb SD card
Sandisk Extreme III 1gb CF card
Extra 1100 mAh battery

PocketTV Team

Originally Posted by flipcody

Pockettv team: I just did a hard reset, installed only pockettv 1.0.3, and still got only 150.25%. Weird that there would be such a difference between roms. Betaplayer (.096) actually picked up performance from A01 to A02 rom. As you said it really doesn't matter at that speed but if you are claiming that it is running at 187% it would be nice to resolve.

Yes, I know, you can certainely ask someone else to run the test on the A01 ROM and confirm what we get, since the device we have is just a normal one, and we get consistent benchmarks for betaplayer.

I think the only way to get to the bottom of this will be for us to install the new ROM, do some tests, and if necessary check with Dell and Intel what difference in their 2700G driver can cause this discrepency.

I totally agree that we should understand and if possible resolve this one.

BTW, the procedure that we use for the PocketTV benchmark is as follow:

1) disable the "Repeat" feature de-select the loop icon just left of the "open file" icon.

2) Open the test file, stop it (so that it is on the first frame)

3) Select Options > File > Benchmark, then tap ok.

4) Tap the display to switch to Fullscreen, then start playback using the RIGHT D-PAD. When I mean RIGHT, that's in reference to the orientation of the fullscreen movie, i.e. in fact it's the UP or DOWN D-PAD if you look at the device in Portrait orientation.

5) Look at benchmark number when the playback ends at the end of the file.

> Betaplayer (.096) actually picked up performance from A01 to A02 rom.

What performance does Betaplayer get with the A02 ROM? We get 185-187% with our A01 ROM, exactly the same that we get with PocketTV.

Dad

Originally Posted by PocketTV Team

at 1.7 Mbit/sec, 90 minute video = 5400 seconds, so it will take 5400 * 1700000 bits = 9,180,000 bits = 1,147,500 bytes = about 1 MB.

I think you dropped a few 0's, thus my GB / MB question earlier. I'd really really really like to be able to get a 90 minute video down to 1MB - getting a DVD down to the size of a Floppy would be a neat trick.

1.7 Mbit/sec, 90 minute video = 5400 seconds, so it will take 5400 * 1700000 bits = 9,180,000,000 bits = 1,147,500,000 bytes = about 1000 MB = 1GB.

What bit rate would you suggest for 320x240?

PocketTV Team

Originally Posted by Dad

I think you dropped a few 0's, thus my GB / MB question earlier.

Oooops you're absolutely correct, I must have missed my dayly dose of cafeine :)

I will correct the post :) thanks for the head's up!

Please check my previous posts, I think the numbers are mostly correct now!

serpa4

If you dont like Pocket TV, don't use it. Nuff said. Don't get ANOTHER BetaPlayer VS PocketTV thing going. Competition is great. Both have free versions, and PTV has a pay version also. Download both free versions and see what you like better.

PocketTV Team

Originally Posted by Dad

What bit rate would you suggest for 320x240?

With MPEG, about 400 Kbit/sec work well. With DivX, try 200 to 300 Kbit/sec. It the quality is too low, try a bit more, but after doubling all those numbers, you will probably have reached the maximum quality.

For VGA (640x480), basically multiply those numbers by 4.

flipcody

Originally Posted by PocketTV Team

BTW, the procedure that we use for the PocketTV benchmark is as follow: 1) disable the "Repeat" feature de-select the loop icon just left of the "open file" icon. 2) Open the test file, stop it (so that it is on the first frame) 3) Select Options > File > Benchmark, then tap ok. 4) Tap the display to switch to Fullscreen, then start playback using the RIGHT D-PAD. When I mean RIGHT, that's in reference to the orientation of the fullscreen movie, i.e. in fact it's the UP or DOWN D-PAD if you look at the device in Portrait orientation. 5) Look at benchmark number when the playback ends at the end of the file.

This is how I benched. I got that method from your Brighthand post.

Betaplayer picked up a few % from A01 to A02 I believe.

__________________
Dell Axim X50v
Kingston 512mb SD card
Sandisk Extreme III 1gb CF card
Extra 1100 mAh battery

PocketTV Team

Originally Posted by flipcody

This is how I benched. I got that method from your Brighthand post. Betaplayer picked up a few % from A01 to A02 I believe.

A few percent is not really significant. We see benchmark results for both Betaplayer and PocketTV vary by about +- 3% from one test to the next. Do you often get more than 187% with Betaplayer on your A02 ROM ?

We'll let you know when we get to the bottom of this ROM performance issue.

Ranma13

Just as an added note, I'm pretty sure the 2700G uses bicubic scaling because I can't see the usual aliasing that bilinear produces.

PocketTV Team

Dad reported to us that with his A02 ROM, he gets results matching ours.

He also noticed that when Resco file explorer is open in the background, the benchmark are lower. This may mean that there is a bug in Resco file explorer, and that for some reason it uses some CPU cycles while in the background.

Dad, please posts your results here, thanks!

Ranma13

For a second there I thought you were talking about your father until I realized that there's a person who has a screen name of 'Dad'.

PocketTV Team

Originally Posted by Ranma13

For a second there I thought you were talking about your father until I realized that there's a person who has a screen name of 'Dad'.

In fact Dad did not use the correct test file. Now he gets 150% with PocketTV on A02 ROM (same as flipcody), but he gets only 170% with betaplayer (we get 185-187% for Betaplayer on A01 ROM).

If anyone has a x50v with A01 ROM (i.e. original old ROM, not upgraded), please run our benchmark (see how on post #65, using file http://www.pockettv.com/mpg/vga/5e-6...1.7Mbps-v2.mpg ), and let us know your results.