94 lines
1.7 KiB
C
94 lines
1.7 KiB
C
#include <SDL/SDL.h>
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#include <SDL/SDL_audio.h>
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#include "common.h"
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void dect_audio_queue(struct dect_audio_handle *ah, struct dect_msg_buf *mb)
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{
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SDL_LockAudio();
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ptrlist_add_tail(mb, &ah->queue);
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SDL_UnlockAudio();
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}
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static void dect_decode_g721(struct g72x_state *codec,
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int16_t *dst, const uint8_t *src,
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unsigned int len)
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{
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unsigned int i;
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for (i = 0; i < len * 2; i += 2) {
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dst[i + 0] = g721_decoder(src[i / 2] >> 4,
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AUDIO_ENCODING_LINEAR, codec);
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dst[i + 1] = g721_decoder(src[i / 2] & 0x0f,
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AUDIO_ENCODING_LINEAR, codec);
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}
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}
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static void dect_audio_dequeue(void *data, uint8_t *stream, int len)
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{
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struct dect_audio_handle *ah = data;
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struct dect_msg_buf *mb;
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int copy;
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len /= 4;
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while (1) {
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if (ah->queue == NULL)
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goto underrun;
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mb = ah->queue;
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copy = mb->len;
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if (copy > len)
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copy = len;
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dect_decode_g721(&ah->codec, (int16_t *)stream, mb->data, copy);
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dect_mbuf_pull(mb, copy);
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if (mb->len == 0) {
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ah->queue = mb->next;
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free(mb);
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}
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len -= copy;
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if (len == 0)
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return;
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stream += 4 * copy;
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}
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underrun:
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printf("audio underrun, missing %u bytes\n", len * 4);
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memset(stream, 0, len * 4);
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}
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struct dect_audio_handle *dect_audio_open(void)
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{
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struct dect_audio_handle *ah;
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SDL_AudioSpec spec = {
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.freq = 8000,
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.format = AUDIO_S16SYS,
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.channels = 1,
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.samples = 512,
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.callback = dect_audio_dequeue,
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};
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ah = malloc(sizeof(*ah));
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if (ah == NULL)
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goto err1;
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ptrlist_init(&ah->queue);
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g72x_init_state(&ah->codec);
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spec.userdata = ah;
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if (SDL_OpenAudio(&spec, NULL) < 0)
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goto err2;
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SDL_PauseAudio(0);
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return ah;
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err2:
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free(ah);
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err1:
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return NULL;
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}
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static void __init dect_audio_init(void)
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{
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if (SDL_Init(SDL_INIT_AUDIO) < 0)
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pexit("SDL_Init");
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}
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