help needed for choppy streaming

[Eowyn]

Hello,
My xmas present to myself was wifi. I got it all to work, and can stream audio and video, but even the audio is very choppy - with too many pauses to make it really worthwhile.

I'm not sure how to improve the situation. Any pointers?

My systems comprises IPAQ 2210, 2003, SDIO WIfi card with 256mb, D-link DI-624 router. The desktop has windows media 9, and windows encoder 9.

[jeffmd]

well first make sure the sd wifi is not in power savings mode.

second, where exactly are you streaming from? I have found shoutcast isnt nearly as full proof as it is on desktop. If its from your pc then..

exactly what software and how are you streaming the audio?

[Eowyn]

I've already turned off power saving mode on the wifi.

I'm using Windows Encoder to stream (from Windows media player on the desktop.


I'm watching the PPC now, streaming audio - The pauses in the music relate to "Buffering"

[Darius Wey]

How strong/weak is your connection?

[Menneisyys]

Hello,
My xmas present to myself was wifi. I got it all to work, and can stream audio and video, but even the audio is very choppy - with too many pauses to make it really worthwhile.

I'm not sure how to improve the situation. Any pointers?

My systems comprises IPAQ 2210, 2003, SDIO WIfi card with 256mb, D-link DI-624 router. The desktop has windows media 9, and windows encoder 9.

What is the encoding speed you use? Actully, there're two bottlenecks in your configuration:

- PWMP itself: it's unable to play videos with bit rates over 300-400 kbps without being choppy/dropped frames

- the SDIO card. Unfortunately, most SDIO cards have very limited throughput. For example, in a 2210+the SanDisk combo, can only stream at 350 kbps. Check out http://www.pocketpcthoughts.com/forums/viewtopic.php?t=28202 for more info on this.

Your only choice is drastically lowering the bit rate (meaning even worse pic/audio quality) to 150-250 kbps and/or getting a CF-based Wi-Fi card. They are an order of magnitude faster than current SD cards. I've benchmarked e.g. the Asus CF Wi-Fi card and got around 270-280 kbytes/s at my file transfer speed test.

[Menneisyys]

How strong/weak is your connection?

Interestingly, on PDA's, because of the severely limited PDA hardware capabilities, (much) weaker signals don't seriously affect the transfer speed. For example, at -85-90 dB (really weak signal, very close to disconnecting on a PL 720) and -63 dB (pretty good and reliable link), I've measured no speed differences. I've posted my becnhmark results at Firstloox at http://www.firstloox.org/forums/showthread.php?t=2562 .

[Darius Wey]

Interestingly, on PDA's, because of the severely limited PDA hardware capabilities, (much) weaker signals don't seriously affect the transfer speed. For example, at -85-90 dB (really weak signal, very close to disconnecting on a PL 720) and -63 dB (pretty good and reliable link), I've measured no speed differences. I've posted my becnhmark results at Firstloox at http://www.firstloox.org/forums/showthread.php?t=2562 .

I wouldn't discount it though. I'm not 100% concerned with the average connection speed being established, but whether its weak enough to cause dropouts - that is, a somewhat unstable connection. It's a serious causative factor I've encountered when helping friends who have had problems streaming in the past.

[Eowyn]

For Audio, the encoding speed at the moment is 70kbps.


Strength of the connection is 100%. As it should be, since I am right next to the router......

[Menneisyys]

Interestingly, on PDA's, because of the severely limited PDA hardware capabilities, (much) weaker signals don't seriously affect the transfer speed. For example, at -85-90 dB (really weak signal, very close to disconnecting on a PL 720) and -63 dB (pretty good and reliable link), I've measured no speed differences. I've posted my becnhmark results at Firstloox at http://www.firstloox.org/forums/showthread.php?t=2562 .

I wouldn't discount it though. I'm not 100% concerned with the average connection speed being established, but whether its weak enough to cause dropouts - that is, a somewhat unstable connection. It's a serious causative factor I've encountered when helping friends who have had problems streaming in the past.

Yeah, dropouts are indeed serious problems, but they are 'bursty' (meaning one, long (a pair of seconds) burst in every 10-50 seconds), unlike problems resulting from the limited decoding capabilities of PWMP and/or the low throughput rate of the SD Wi-Fi card.

So, if there're small dropouts in every second, I don't think it's a problem of a weak signal but the computing power of the 2210/WMP's/the SD card's being slow. This is what the topic starter haven't really elaborated on as yet.

EDIT: there has been an answer to the later q in the meantime. So, the problem is clearly related to the low throughput of the SD card, which can't be helped without drastically lowering the bit rate.

[JvanEkris]

What do you use to stream the media?

Jaap

[Menneisyys]

For Audio, the encoding speed at the moment is 70kbps.


OIC. Not even 70 kbps is streamed OK?! It is strange. I've streamed audio a lot over BT (= 200 kbps max. practical speed), and, with 50-100% signal strength (BT is far more affected by weak signals than Wi-Fi, speed-wise - BT's speed radically lowers with weaker signals, unlike Wi-Fi, which "only" suffers long-lasting dropouts), PWMP's sound was never jerky.

Could you try the same over BT/ActiveSync (just listen to the audio over the alternative connection techniques)? Just to see whether the problem is indeed related to Wi-Fi and not to the 2210/the desktop. I don't think Wi-Fi is THAT bad, there most be something else. So, listen to the desktop encoder on your AS-connected PDA.

[Darius Wey]

What do you use to stream the media?

I believe it was Windows Media Encoder, as mentioned in an earlier post.

[Darius Wey]

OIC. Not even 70 kbps is streamed OK?! It is strange.

That's what I thought too. ;)

If what Menneisyys has suggested does not work for you, do you have another device with Wi-Fi access? For example, a laptop with Wi-Fi? If so, see if you can set the media to stream over to the laptop and see if you get jerky sounds in that scenario. That way, we can probably source the problem to your PDA or the computer streaming the media.

[Eowyn]

I don't have any Bluetooth devices (peering into wallet and considering HP Bluetooth stereo headphones )


Umm... how do you stream over ActiveSync?

[Eowyn]

I don't have any other Wifi.

[Eowyn]

Figured out the streaming via active sync..

[Eowyn]

Streaming over ActiveSync seems to be working ok (for audio anyway). That's disappointing, because it implies the problem is in the wifi, not the encoder.

- Just had one moment of pausing for buffering... but much less frequent than with the wifi.

[Menneisyys]

Streaming over ActiveSync seems to be working ok (for audio anyway). That's disappointing, because it implies the problem is in the wifi, not the encoder.

- Just had one moment of pausing for buffering... but much less frequent than with the wifi.

OIC, that's good news, meaning we know where (Wi-Fi) the problem resides. Now, another test: could you test file transfer thoroughput speed from your desktop computer in the background? That is, share a desktop directory, map it on your PDA and just copy a 5-10 Mbyte file from the desktop to the main memory of your PDA, preferably with Resco Explorer, and, right after the file transfer has been started, switch to, e.g., Today, so that the file transfer takes place in a background thread (and, in this case, also task - but the diff. between tasks and threads won't affect the results in this case). If the file throughput speed is also very low, then it's not a problem with PWMP / desktop media encoder either.

The problem may (or, I think, MUST) be the fact that any (Wi-Fi / USB host / card-based) PPC-based transfer works far slower in a background thread than in a foreground one. This isn't relevant with built-in / CF-based Wi-Fi units because their 300 kbytes/s practical throughput may become some 40-100 kbytes/s when run in a background thread; the 300 kbit/s practical throughput of the SD Wi-Fi card, however, when run in a background thread, may suffer the same speed reduction (in the worst case, the speed may be reduced to one-tenth of the original speed!), and this is why WMP isn't even able to play 70 kbps streams without problems. This is certainly a very severe limitation of the WinCE platform/MS's drivers, and this is what the test outlined above investigates.

EDIT 2-3 minutes after my initial post: added some additional testing methologies.

[Eowyn]

I'm not sure how to check the file transfer speed. Did you mean by stopwatch or by looking at the "Current TX Rate" for the WIFI card (which says 11 Mb/s.)

[Menneisyys]

I'm not sure how to check the file transfer speed. Did you mean by stopwatch or by looking at the "Current TX Rate" for the WIFI card (which says 11 Mb/s.)

With a stopwatch. I'd also add that there is no need to switch to an entirely different app (e.g., Today) - just open the start menu (it's another thread/task, so the file copier becomes a background one) and make sure it remains open. That way, you'll always see how the copying fares.

[Eowyn]

ok, a 6.301Mb file took approx 210 seconds (3min30sec) = 30Kbytes / second.

[Menneisyys]

ok, a 6.301Mb file took approx 210 seconds (3min30sec) = 30Kbytes / second.

In a background thread? Then, it's slightly less than Tom's Hardware's results. However, 30 kbytes/s should be enough to stream even 240 kbps streams (OK, a bit less, because of the overhead, but still far more than 70 kbps).

I think the only solution is getting/loaning a CF Wi-Fi card. They have no speed problems, unlike the SD-based cards.

[jeffmd]

if you got even one rebuffer while hooked up via active synch cable, then this is clearly just windows media player being sensitive. It is more sensitive to the wifi because there is more overhead, and the wifi controllers are setup to multi task (no one connection has dominance) unlike a straight serial connection.

How ever I also find that your method of streaming music pretty bad. I recomend you instead get resco's file explorer (and compleatly ditch MS explorer cause it dosnt offer much of any network support) and simply browse your computers file shares and use the mp3 player of your choice (betaplayer, pocket player, ect) to play your mp3s. That way you get to choose what you want to play from your ppc, and no nasty re-encode process to make it sound worse.

[phantom4099]

I tried the windows media player today to listen to music, and I experienced choppy music. So I will continue to use pocket movie player (free), and a program that allows me to access my shared files while I am on my Ipaq 3955.

Wyatt W.