Hi Frank, At Wed, 5 Feb 2003 00:34:41 +0100, Frank Neumann wrote: > > > Hi list, > > I have written a small helper program (for myself so far) that should allow > me to get a backup of all data from a Korg M3r expander through the ALSA > rawmidi API. I have written a first version that opens the rawmidi device, > tells the user to "start the dump on the M3r", and then waits for the > beginning of the SysEx data and stores that into a file. This one works > nicely. > > Then, I modified it just a bit so that it does not passively wait but > instead actively sends the SysEx sequence for "Get All Program/Combination/ > Drum/Global data" and then records everything that comes back. > > Normally, according to the M3r's SysEx implementation in its manual, > this should give the same output, exactly 23963 bytes. > However, the second version loses about 130 bytes during the transfer. > The strange thing is that the beginning of the data (SysEx header: > F0 42 30 24...) is fine, and starting around byte 700 the data is exactly > the same as in the correct output, including the EOX (F7) at the very end of > the output. But somewhere in this first part, data is lost. just to be sure: any realtime events can come in?
> Even worse: Starting the same program with the same arguments gives > slightly differing number of output bytes each time: ... > This number was observed to be in a range of +-20 bytes. > Could anyone explain this? Though the MIDI interface on the PC side > is in a cheapo Soundblaster PCI512 card, I don't think it's responsible > for data losses. To me this looks rather like a rawmidi problem. The > program really doesn't do much more but snd_rawmidi_open, snd_rawmidi_write, > snd_rawmidi_read, snd_rawmidi_drain and snd_rawmidi_close. as Clemens wrote, please check the buffer overruns. the buffer overruns are shown in /proc/asound/card0/midiX proc file but only during the midi is opened for read. ciao, Takashi ------------------------------------------------------- This SF.NET email is sponsored by: SourceForge Enterprise Edition + IBM + LinuxWorld = Something 2 See! http://www.vasoftware.com _______________________________________________ Alsa-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/alsa-devel
