From bdab6c12d4332523fdbd8967c1233b3708f4883e Mon Sep 17 00:00:00 2001 From: Jeff Epler Date: Mon, 11 May 2020 08:51:41 -0500 Subject: MP3Decoder: take advantage of background callback Before this, the mp3 file would be read into the in-memory buffer only when new samples were actually needed. This meant that the time to read mp3 content always counted against the ~22ms audio buffer length. Now, when there's at least 1 full disk block of free space in the input buffer, we can request that the buffer be filled _after_ returning from audiomp3_mp3file_get_buffer and actually filling the DMA pointers. In this way, the time taken for reading MP3 data from flash/SD is less likely to cause an underrun of audio DMA. The existing calls to fill the inbuf remain, but in most cases during streaming these become no-ops because the buffer will be over half full. --- shared-module/audiomp3/MP3Decoder.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'shared-module/audiomp3/MP3Decoder.h') diff --git a/shared-module/audiomp3/MP3Decoder.h b/shared-module/audiomp3/MP3Decoder.h index 9ee1d0949..f91f102a2 100644 --- a/shared-module/audiomp3/MP3Decoder.h +++ b/shared-module/audiomp3/MP3Decoder.h @@ -28,6 +28,7 @@ #ifndef MICROPY_INCLUDED_SHARED_MODULE_AUDIOIO_MP3FILE_H #define MICROPY_INCLUDED_SHARED_MODULE_AUDIOIO_MP3FILE_H +#include "supervisor/background_callback.h" #include "extmod/vfs_fat.h" #include "py/obj.h" @@ -36,6 +37,7 @@ typedef struct { mp_obj_base_t base; struct _MP3DecInfo *decoder; + background_callback_t inbuf_fill_cb; uint8_t* inbuf; uint32_t inbuf_length; uint32_t inbuf_offset; -- cgit v1.2.3