Posts Tagged: ‘mp3’

STM32F4 Discovery / MP3 / Libmad / SDCard / USB-ouput / ChibiOS 2.6.1

11/08/2013 Posted by admin

Just an update for ChibiOS 2.6.1 of the code I have to run Libmad on the STM32F4 Discovery board.

Code

 

MP3 Audio Decoder on STM32F4 Discovery (updated 30/10/2012) – ChibiOS 2.4.2

09/23/2012 Posted by admin

I like the work that was done by Marco W. (watz) on that forum.

Using the same hardware (SD Card connected to PA5/6/7 and PC4), ChibiOS 2.4.x and LibMAD (instead of Helix),
I finally have managed to get some output…

Most of the code comes from Marco W. ‘s work, I only tried to replace the stm32 audio discovery code by
functions provided by chibiOS (for I2C / I2S via SPI code and DMA).

Here is the code (you need to have ChibiOS sources too).

Update 23/09/2012 : Thanks to a comment by Deanrock, I have repackaged the source code with the I2C
modification & I have tested recompilation using a current Sourcery Code Bench (gcc version 4.6.3 – Sourcery CodeBench Lite 2012.03-56) and Chibios 2.4.2 (this version does not require any patching, just deflate fatfs from the ‘ext’ folder).

Here is the New code

Update 30/10/2012 : with my first tests, I had to enable the chibiOS debugs to get a stable behaviour. It looks like it is running just fine without, provided that -O2 is used (instead of -Os) and that CORTEX_USE_FPU is set to FALSE.

User button is used to skip to the next file.
This one was only tested with Chibios 2.4.2.

Here is the New code

MP3 Audio Decoder on STM32F4 Discovery (update)

03/15/2012 Posted by admin

I have made small updates to the code :

- Using -Os instead of -O3 gives much better performance (load is <20%)
- Used 'ssat' instruction for clipping output instead of the basic 'minimad.c' code example.

New code/Binary is here .

MP3 in : lg 879457
...
Decoding return 0
Timing Max. 518 19.82 %
Timing Min. 437 16.72 %
Timing Moy. 466 17.83 %

MP3 Audio Decoder on STM32F4 Discovery

03/07/2012 Posted by admin

The ST Firmware for STM32F4 Discovery includes a simple Audio demo that
demonstrates a Wave player (directory Project/Audio_playback_and_record).

From that project, I derived an Audio_playback_MP3 that plays an embedded MP3
stream (the same audio as in the ST example), but the audio is now around 55 seconds
instead of the original 5 seconds.

The MP3 decoder lib used is the libmad v. 0.15.1 .
(Lire la suite…)