Players, playing data from RAM

[Chipp Walters]

Hi Dave,

My best thinking on this subject would be to try and discover what's
happening on the other machines. If you can't reproduce the errors, perhaps
you can write a utility to see (some things to possibly check for):

1) What version of the OS they are using
2) If QT is installed or not
3) logs the time it takes to 'rename' the files and other
4) other hardware considerations (cpu speed, drive space, etc)
5) Is a virus checker involved

I've found sometimes the hardest part of debugging is trying to reproduce
the error!

best,

Chipp


> -----Original Message-----
> From: metacard-admin at lists.runrev.com
> [mailto:metacard-admin at lists.runrev.com]On Behalf Of Dave Cragg
> Sent: Thursday, June 12, 2003 6:39 AM
> To: metacard at lists.runrev.com
> Subject: Players, playing data from RAM
>
>
> Hi
>
> My main question is whether there is a way to play audio data through
> a Player object without linking the Player to an external file or url.
>
> I think the answer is no, but I'm really hoping I've missed something.
>
> Some background:
>
> I developed a language learning application that plays a conversation
> as a series of audio clips. Originally the clips were in au format
> and were played with the "play audioclip" command. When one clip
> ended, the next was played. All the clips for a single conversation
> were imported to a single stack. Open the stack (downloaded from an
> ftp or http server) and the clips are all in RAM. This worked fine,
> and the playback was seamless.
>
> I've recently had to change the audio format to mp3. Unfortunately,
> you can't play mp3 with the "play" command and have to use a Player
> object. This means linking to a file (set the filename). I tried to
> keep to a similar strategy. The mp3 clips for a single conversation
> are stored as custom properties of a stack. The stack is downloaded
> from the web. The clips are written as temporary files on the local
> drive. The  clips are played back through a player in sequence.
>
> On my machines (and most others it seems) this gives acceptable
> performance. But I've had reports of long pauses (up to 5 seconds)
> between clips from one group of users. These users are far away, so I
> can't see eactly what is happening. But even if I find out they have
> some anti-virus software or something else that is delaying the
> setting of filenames, I prefer to avoid the problem happening
> elsewhere.
>
> The solutions I've tried so far:
>
> -- use a single player, change the filename after each clip (works
> fine here, gives the longest pauses on the problem machines)
>
> -- use multiple players (one per clip), set the filenames when the
> lesson opens. This gives better performance, but when the Players are
> unbuffered, the pauses are still too long. When the Players are
> buffered, the pauses are acceptable, but there is a long delay (up to
> 15 seconds) on the problem machines while the filenames are set for
> each player.
>
> Solutions I want to avoid:
>
> I could join all the clips into a single audio file. But as each clip
> plays, some corresponding text is hilited in a field. I'd have to
> completely redo how the text segments are linked to the playing audio
> -- work I'd prefer to avoid.
>
> Linking to a url instead of a file offers a partial solution. You can
> load the url first, and then the Player will play the sound from the
> cached url. However, after the audio is first downloaded from the
> web, it has to be stored locally (a custom cache) to avoid further
> downloads, which means the Player then has to deal with files, not
> http/ftp urls. (As far as I can determine, you can't load
> "file/binfile" urls.)
>
> What I really want is something like "set the data of player 1 to
> <some data>.
>
> Any ideas anyone?
>
> Cheers
> Dave
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