f6209cc959
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@13215 a1c6a512-1295-4272-9138-f99709370657
321 lines
7.5 KiB
C
321 lines
7.5 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2005 by Nick Lanham
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*
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* All files in this archive are subject to the GNU General Public License.
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* See the file COPYING in the source tree root for full license agreement.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#include "autoconf.h"
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#include <stdlib.h>
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#include <stdbool.h>
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#include <memory.h>
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#include "debug.h"
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#include "kernel.h"
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#include "sound.h"
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#include "SDL.h"
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static bool pcm_playing;
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static bool pcm_paused;
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static Uint8* pcm_data;
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static size_t pcm_data_size;
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static SDL_AudioSpec obtained;
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static SDL_AudioCVT cvt;
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extern bool debug_audio;
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static void sdl_dma_start(const void *addr, size_t size)
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{
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pcm_playing = true;
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SDL_LockAudio();
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pcm_data = (Uint8 *) addr;
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pcm_data_size = size;
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SDL_UnlockAudio();
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SDL_PauseAudio(0);
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}
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static void sdl_dma_stop(void)
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{
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pcm_playing = false;
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SDL_PauseAudio(1);
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pcm_paused = false;
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}
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static void (*callback_for_more)(unsigned char**, size_t*) = NULL;
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void pcm_play_data(void (*get_more)(unsigned char** start, size_t* size),
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unsigned char* start, size_t size)
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{
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callback_for_more = get_more;
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if (!(start && size)) {
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if (get_more)
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get_more(&start, &size);
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else
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return;
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}
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if (start && size) {
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sdl_dma_start(start, size);
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}
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}
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size_t pcm_get_bytes_waiting(void)
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{
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return pcm_data_size;
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}
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void pcm_mute(bool mute)
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{
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(void) mute;
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}
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void pcm_play_stop(void)
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{
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if (pcm_playing) {
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sdl_dma_stop();
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}
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}
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void pcm_play_pause(bool play)
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{
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size_t next_size;
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Uint8 *next_start;
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if (!pcm_playing) {
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return;
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}
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if(pcm_paused && play) {
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if (pcm_get_bytes_waiting()) {
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printf("unpause\n");
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SDL_PauseAudio(0);
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} else {
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printf("unpause, no data waiting\n");
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void (*get_more)(unsigned char**, size_t*) = callback_for_more;
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if (get_more) {
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get_more(&next_start, &next_size);
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}
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if (next_start && next_size) {
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sdl_dma_start(next_start, next_size);
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} else {
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sdl_dma_stop();
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printf("unpause attempted, no data\n");
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}
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}
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} else if(!pcm_paused && !play) {
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printf("pause\n");
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SDL_PauseAudio(1);
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}
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pcm_paused = !play;
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}
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bool pcm_is_paused(void)
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{
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return pcm_paused;
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}
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bool pcm_is_playing(void)
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{
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return pcm_playing;
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}
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void pcm_set_frequency(unsigned int frequency)
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{
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// FIXME: Check return values
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SDL_BuildAudioCVT(&cvt, AUDIO_S16SYS, 2, frequency,
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obtained.format, obtained.channels, obtained.freq);
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}
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/*
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* This function goes directly into the DMA buffer to calculate the left and
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* right peak values. To avoid missing peaks it tries to look forward two full
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* peek periods (2/HZ sec, 100% overlap), although it's always possible that
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* the entire period will not be visible. To reduce CPU load it only looks at
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* every third sample, and this can be reduced even further if needed (even
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* every tenth sample would still be pretty accurate).
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*/
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#define PEAK_SAMPLES (44100*2/HZ) /* 44100 samples * 2 / 100 Hz tick */
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#define PEAK_STRIDE 3 /* every 3rd sample is plenty... */
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void pcm_calculate_peaks(int *left, int *right)
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{
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long samples = (long) pcm_data_size / 4;
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short *addr = (short *) pcm_data;
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if (samples > PEAK_SAMPLES)
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samples = PEAK_SAMPLES;
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samples /= PEAK_STRIDE;
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if (left && right) {
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int left_peak = 0, right_peak = 0, value;
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while (samples--) {
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if ((value = addr [0]) > left_peak)
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left_peak = value;
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else if (-value > left_peak)
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left_peak = -value;
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if ((value = addr [PEAK_STRIDE | 1]) > right_peak)
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right_peak = value;
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else if (-value > right_peak)
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right_peak = -value;
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addr += PEAK_STRIDE * 2;
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}
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*left = left_peak;
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*right = right_peak;
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}
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else if (left || right) {
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int peak_value = 0, value;
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if (right)
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addr += (PEAK_STRIDE | 1);
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while (samples--) {
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if ((value = addr [0]) > peak_value)
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peak_value = value;
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else if (-value > peak_value)
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peak_value = -value;
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addr += PEAK_STRIDE * 2;
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}
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if (left)
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*left = peak_value;
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else
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*right = peak_value;
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}
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}
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static long write_to_soundcard(Uint8 *stream, int len, FILE *debug) {
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Uint32 written = (((Uint32) len) > pcm_data_size) ? pcm_data_size : (Uint32) len;
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if (cvt.needed) {
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cvt.buf = (Uint8 *) malloc(written * cvt.len_mult);
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cvt.len = written;
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memcpy(cvt.buf, pcm_data, written);
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SDL_ConvertAudio(&cvt);
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memcpy(stream, cvt.buf, cvt.len_cvt);
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if (debug != NULL) {
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fwrite(cvt.buf, sizeof(Uint8), cvt.len_cvt, debug);
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}
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free(cvt.buf);
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} else {
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memcpy(stream, pcm_data, written);
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if (debug != NULL) {
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fwrite(pcm_data, sizeof(Uint8), written, debug);
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}
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}
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return written;
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}
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void sdl_audio_callback(void *udata, Uint8 *stream, int len)
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{
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Uint32 have_now;
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FILE *debug = (FILE *) udata;
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/* At all times we need to write a full 'len' bytes to stream. */
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/* Write what we have in the PCM buffer */
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if (pcm_data_size > 0) {
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have_now = write_to_soundcard(stream, len, debug);
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stream += have_now;
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len -= have_now;
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pcm_data += have_now;
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pcm_data_size -= have_now;
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}
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/* Audio card wants more? Get some more then. */
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while (len > 0) {
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if (callback_for_more) {
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callback_for_more(&pcm_data, &pcm_data_size);
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} else {
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pcm_data = NULL;
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pcm_data_size = 0;
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}
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if (pcm_data_size > 0) {
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have_now = write_to_soundcard(stream, len, debug);
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stream += have_now;
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len -= have_now;
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pcm_data += have_now;
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pcm_data_size -= have_now;
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} else {
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DEBUGF("sdl_audio_callback: No Data.\n");
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sdl_dma_stop();
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break;
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}
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}
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}
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int pcm_init(void)
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{
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SDL_AudioSpec wanted_spec;
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FILE *debug = NULL;
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if (debug_audio) {
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debug = fopen("audiodebug.raw", "wb");
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}
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/* Set 16-bit stereo audio at 44Khz */
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wanted_spec.freq = 44100;
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wanted_spec.format = AUDIO_S16SYS;
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wanted_spec.channels = 2;
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wanted_spec.samples = 2048;
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wanted_spec.callback = sdl_audio_callback;
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wanted_spec.userdata = debug;
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/* Open the audio device and start playing sound! */
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if(SDL_OpenAudio(&wanted_spec, &obtained) < 0) {
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fprintf(stderr, "Unable to open audio: %s\n", SDL_GetError());
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return -1;
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}
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sdl_dma_stop();
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return 0;
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}
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void pcm_postinit(void)
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{
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}
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