midibox_sd_card_sample_player
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| midibox_sd_card_sample_player [2011/11/10 22:37] – created leeby5 | midibox_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 | + | 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, |
| ===== Hardware ===== | ===== Hardware ===== | ||
| You will need: | You will need: | ||
| - | * Midibox LPC1769 core - see http:// | + | * Midibox LPC1769 core (or STM32 now, but that has limited polyphony due to core speed) |
| - | * I2C DAC (ie TDA1543) - see http:// | + | * I2C DAC (ie TDA1543 |
| * SD card interface - see http:// | * SD card interface - see http:// | ||
| * 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 | + | It has now been run on both LPC1769 |
| ===== Creating files on SD card ===== | ===== Creating files on SD card ===== | ||
| - | The system currently looks for a file called 'bank.1' | + | As of rev 1371 on the SVN, it now reads a file called 'player.cfg' |
| - | 0x39 c_a.raw | + | midichannel 1 |
| - | 0x3a c_bf.raw | + | |
| - | Where the first number is the MIDI note number in Hex, and after the space is the filename of the sample to play (up to 8.3 characters). | + | 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 ' | ||
| + | |||
| + | 0x39 0 0031 c_a.raw | ||
| + | 0x3a 1 0000 c_bf.raw | ||
| + | |||
| + | where the first number is the MIDI note number in Hex, the single digit is 0=no sample hold, 1=sample hold (ie for drums etc), the 4 digit number is a decimal value for an envelope decay (0000=no decay, and up to 1023 is supported) | ||
| 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: 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) |
| + | |||
| + | 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! | ||
| ===== Other notes ===== | ===== Other notes ===== | ||
| Line 30: | Line 39: | ||
| * It is coded to play up to 8 notes polyphony, but depending on the card speed you may get only 5-6 from time to time... | * It is coded to play up to 8 notes polyphony, but depending on the card speed you may get only 5-6 from time to time... | ||
| * If you watch the debug output in MIOS Studio, it reports the samples loaded on initialisation and also if the safety net is kicking in | * If you watch the debug output in MIOS Studio, it reports the samples loaded on initialisation and also if the safety net is kicking in | ||
| + | |||
| + | ===== 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) | ||
| + | * Envelope filtering and voice assignment now runs as a seperate MIOS task (increasing time available for sample read/ | ||
| + | * We can now do a decay envelope, and this is specified for each individual samples (eg staccato / legato) | ||
| + | * 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, | ||
| + | * 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 | ||
| ===== To do ===== | ===== To do ===== | ||
| - | * Cache FAT directory in RAM (currently it periodically needs to re-read it) | + | * Support more MIDI events |
| - | * Implement | + | * Make the bank file parsing more robust, and support comments, invalid lines etc |
| - | * Perform simple envelope filtering | + | |
| - | * Implement more MIDI functions (currently literally only note on and off right now on channel 1) | + | ===== Files ===== |
| + | * Now uploaded to the MIOS32 SVN at: | ||
| + | * [[http:// | ||
| + | ===== More info ===== | ||
| + | * A write up and more info on my site at [[http:// | ||
midibox_sd_card_sample_player.1320964638.txt.gz · Last modified: 2011/11/10 22:37 by leeby5