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midibox_sd_card_sample_player

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midibox_sd_card_sample_player [2011/12/06 23:32] – leeby5midibox_sd_card_sample_player [2012/05/29 21:14] (current) – leeby5
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 ====== MIDIbox SD Card Polyphonic Sample Player ====== ====== MIDIbox SD Card Polyphonic Sample Player ======
-This is a brief description of a project in progress to play back samples in real time from an SD card to an I2S based DAC on the Midibox. It will play a number of samples simultaneously, mixing the output to the DAC, the number of samples depends upon the performance of the SD card.+This is a brief description of a project to play back samples in real time from an SD card to an I2S based DAC on the Midibox. It will play a number of samples simultaneously, mixing the output to the DAC, the number of samples depends upon the performance of the SD card.
  
 ===== Hardware ===== ===== Hardware =====
 You will need: You will need:
  
-  * Midibox LPC1769 core - see http://www.ucapps.de/mbhp_core_lpc17.html (or make a minimal setup like I did) +  * Midibox LPC1769 core (or STM32 now, but that has limited polyphony due to core speed) - see http://www.ucapps.de/mbhp_core_lpc17.html (or make a minimal setup like I did) 
-  * I2C DAC (ie TDA1543) - see http://www.ucapps.de/mbhp_i2s.html but MAKE SURE YOU RUN THE TDA1543 DAC FROM 5V AS 3.3V SOUNDS BAD+  * I2C DAC (ie TDA1543 or similar) - see http://www.ucapps.de/mbhp_i2s.html but MAKE SURE YOU RUN THE TDA1543 DAC FROM 5V AS 3.3V SOUNDS BAD
   * SD card interface - see http://www.ucapps.de/mbhp_sdcard.html   * SD card interface - see http://www.ucapps.de/mbhp_sdcard.html
   * SD card formatted as FAT (NOT FAT32 - important as FAT32 performance currently isn't fast enough) - this limits you typically to cards <=2GB   * SD card formatted as FAT (NOT FAT32 - important as FAT32 performance currently isn't fast enough) - this limits you typically to cards <=2GB
   * MIDI data via USB or the standard Midi in   * MIDI data via USB or the standard Midi in
  
-I have currently only tested this on the LPC1769 based MIOS32 Midibox. It should work in theory if compiled for the STM32, but I don't have one to try!+It has now been run on both LPC1769 and STM32 cores... :-)
  
 ===== Creating files on SD card ===== ===== Creating files on SD card =====
-The system currently looks for a file called 'bank.1' on the SD card root. This is a text file, but must have Unix style line feeds (not DOS style) - just use your friendly programmer's file editor to create one (or make it on a Mac :-) ). It will read up to 64 lines from this file, each line mapping a MIDI note, and the format is e.g:+As of rev 1371 on the SVN, it now reads a file called 'player.cfg' from the SD card which is a UNIX style file (there's an example in the SVN) which contains name value pair separated by a space. At present it only supports two parameters, eg: 
 + 
 +  midichannel 1 
 +  lee_hw 1 
 + 
 +The first one (obviously) sets the midi channel for the player. The second value is to enable my simple rotary bank switch on J10 (you probably want this set to zero if you have a real midibox core, and want to use MIDI program change to select the bank). 
 + 
 +The system currently looks for a file called 'bank.1' on the SD card root by default (and bank.2, bank.3 etc as you send a program change). This is a text file, but must have Unix style line feeds (not DOS style) - just use your friendly programmer's file editor to create one (or make it on a Mac :-) ). It will read up to 64 lines from this file, each line mapping a MIDI note, and the format is e.g:
  
   0x39 0 0031 c_a.raw   0x39 0 0031 c_a.raw
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 It looks for the samples in the root of the SD card. It looks for the samples in the root of the SD card.
  
-The sample format is fixed as: monophonic (1 channel) 44.1kHz 16 bit RAW little endian. Quite a mouthful. Basically use Audacity, Soundforge etc to convert whatever samples you have into this format.+The sample format is fixed as: monophonic (1 channel) 44.1kHz 16 bit RAW signed little endian. Quite a mouthful. Basically use Audacity, Soundforge etc to convert whatever samples you have into this format.
  
 Currently you have to provide a note mapping for each note you want to sound, and usually therefore you will need to generate a sample of the right pitch for each note. This is a lot of samples for a full key range, but hey hopefully you only have to do this once! Currently you have to provide a note mapping for each note you want to sound, and usually therefore you will need to generate a sample of the right pitch for each note. This is a lot of samples for a full key range, but hey hopefully you only have to do this once!
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 ===== Latest features ===== ===== Latest features =====
 +  * Now supports a config file on the SD card
   * Now supports MIDI program change to load banks from the SD card (eg for patch 1 it will load bank.1, patch 2 it will load bank.2 etc)   * Now supports MIDI program change to load banks from the SD card (eg for patch 1 it will load bank.1, patch 2 it will load bank.2 etc)
   * Envelope filtering and voice assignment now runs as a seperate MIOS task (increasing time available for sample read/mixing, increased responsiveness and more stability)   * Envelope filtering and voice assignment now runs as a seperate MIOS task (increasing time available for sample read/mixing, increased responsiveness and more stability)
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   * You can do sample hold per sample, eg have a bank where drum sounds are on some notes, and other non-hold samples such as bass are on other notes   * You can do sample hold per sample, eg have a bank where drum sounds are on some notes, and other non-hold samples such as bass are on other notes
   * It now supports velocity sensitivity, and this is translated to volume via a look up table   * It now supports velocity sensitivity, and this is translated to volume via a look up table
-  * Bank switching is supported on the fly (ie without a reboot) - though program change isn't there yet+  * Bank switching (MIDI program change) is supported on the fly (ie without a reboot)
   * Thanks to TK the sector positions on the SD card are cached leading to much better stability with multiple notes sounding   * Thanks to TK the sector positions on the SD card are cached leading to much better stability with multiple notes sounding
  
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   * Now uploaded to the MIOS32 SVN at:   * Now uploaded to the MIOS32 SVN at:
   * [[http://svnmios.midibox.org/listing.php?repname=svn.mios32&path=%2Ftrunk%2Fapps%2Fsynthesizers%2FSD+card+sample+player%2F]]   * [[http://svnmios.midibox.org/listing.php?repname=svn.mios32&path=%2Ftrunk%2Fapps%2Fsynthesizers%2FSD+card+sample+player%2F]]
 +
 +===== More info =====
 +  * A write up and more info on my site at [[http://www.bassmaker.co.uk|Bassmaker]]
midibox_sd_card_sample_player.1323214364.txt.gz · Last modified: 2011/12/06 23:32 by leeby5