MP3@64 stuttering and skipping

[AmigaNut08]

Hi all. It seems that i am not having any luck at all with any new Amiga hardware i get these days. I just tried out my new MP3@64 Audio decoder in my A1200 only to have the audio skip and stutter so bad that it is torture to try and listen too it. I am using the mp3at64mpeg.device and Amplifier to play the mp3's. I tried different settings but to no avail. After thinking that Amplifier might be the problem i tried an mp3 with the shell based player that comes with the mp3at64mpeg.device, mp3at64play but i get the same results.

 In the readme is the following.

Known Problems
~~~~~~~~~~~~~~
- Sometimes the sound is interrupted for a short period. Seems to be a  bug
  in  the  timer.device  that  sometimes causes interrupts to be delayed. I
  tried very small intervals, but it still remained, so I guess it's either
  a bug in timer, or the system interrupt load causes high latencies.

Is anyone else getting stuttering and skipping audio or is it just my luck to be the only one affected??? If others are getting smooth playback i'll try this card in my A2000 equipped with a Buddha Phoenix card, which is the Amiga i intended to use this on originally.

[AmigaNut08]

What OS are you running on your A1200? Maybe something is interfering. You might try to boot without startup-sequence and check if you get better results with the command line player then (not sure if this will work though).

I am running OS3.1. Although the MP3@64 is not meant to put a load on the Amiga's CPU the Apollo 1240 (040@40Mhz) felt some strain as the system was very laggy and the screen flashed black very quick(like a blink) on 2 occasions while playing mp3's.

 I was going to try the command line player with no startup- sequence but i then got side tracked and forgot. I cant be bothered opening the A1200 up now to try, plus i am more anxious to see how it performs in the A2000, which is the Amiga i really want to use it in.

Cheers

[AmigaNut08]

Have you tried to make the (pre)buffer as big as possible ? If set to low, you'll get the effect as described.

x303

I tried double the standard setting and then tripled the values. But still not acceptable. I'll try some over the top values and see if that helps next time.

[AmigaNut08]

How much RAM do you have installed?

I have 18 meg all up. the standard 2 meg chip on the A1200 and 16 meg on the Apollo 1240. After boot up and the player loaded, i have over 13meg free.

[AmigaNut08]

Sorry, bit late onto this thread, but can any of you confirm that you're using the MP3@64 off the internal clockport on an A1200? And if so, how did you achieve this? Using a clockport riser I guess? Also, how is performance? Like, what's the highest bitrate you can play on your machine and with what software?

I'm currently using a MAS player for an ongoing MP3 jukebox project, and I might consider going the MP3@64 route if it's less CPU hungry than the current parallel port transfers...

I did use the MP3@64 off the internal clockport on my A1200. I used a clockport extension cable (Male header to Female header) that i ordered from Amigakit. The MP3@64 can play any bit rate. The player i used was Amigaamp. The sound quality (when it did not stutter) is brilliant. I would recommend purchasing the MP3@64 as it decodes the MP3 audio without the use of the Amiga's CPU. Now if only it played without stuttering. I am going to have to try this in my A2000 this weekend and see if it performs better.

[AmigaNut08]

Thanks for that! Yeah, it's the stuttering I'm worried about - I was thinking it could be a factor of DMA timing or something which affects certain A1200 motherboards. The MAS Player uses the same decoding chip as the MP3@64, but like I said in my previous post, just takes a little bit of CPU power to do a serialisation of the data before sending it out the parallel port. It's a shame there's nobody living nearby I could borrow one from to test it

DMA timing is what i am thinking also. Remember the timing issues A1200's had when faster cpu cards came out for it. A mod had to be performed on the mobo because of timing issues. I was also unable to get my ethernet adapter to work through the credit card slot as i was told my mobo also needed a mod done because the port would not reset with the given software. I was unable to connect to my router so i ended up selling the ethernet card. Not all A1200's suffer from these above mentioned issues (thank god the Apollo1240 worked as i believe this mobo was modded before i bought it) but knowing my luck i am probably in the minority of people that have had issues like this.

PS: Anyone out there using the MP3@64 in an A1200??

[AmigaNut08]

Hi all,
 Here's the latest after i tried the MP3@64 in my A2000 with the Buddha card.
 
1st i installed all the needed software, then connected the MP3@64 to the Buddha. I then fired up the A2000. I was so excited during bootup that all was going ok, untill i saw a heap of smoke coming from the MP3@64. Man i fried the chip that sits in the middle of the MAS chip and the crystal. I must have had the orientation of the cable f*cked up. I plugged it in with the red line on the ribbon cable running the same way (Left) it did when i plugged it into my A1200. I guess i should have had the red line to the right of the card. At the time i also had the floppy power cable in the Buddha to power a 2.5" HD. That would not have caused the chip to fry would it???

 Ok, this little incident isnt going to put me off from having my Amiga play MP3's in full 16 bit stereo sound as i am going to purchase another card. The question i have now, (i should have asked this 1st as it would have saved me $100) when i receive my new MP3@64, which way does the red line on the cable face on the Buddha. The HD cable has the red line on the ribbon cable facing to the right. Do i follow the same orientation as the HD cable and have the red line on the MP3@64 ribbon cable also facing right?? Also does the Red line on the ribbon stay the same (its to the left of the audio plugs facing away from the card) as it does when plugged in the A1200. or another way to ask so i dont confuse people as i am confusing myself as i write, does the cable that is attached to the MP3@64 stay the same on the card if it is used on an A1200 or a Buddha??


Cheers

[AmigaNut08]

Hi,
 There is a mark showing pin 1 on the 2 ide connectors on the Buddha card but i dont think there was an indicator showing pin 1 on the clockport connector.
 Well luckily the Buddha card is still ok as i am using it with a HD connected to it.