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comparison src/audio/alsa/SDL_alsa_audio.c @ 4332:67e799ffcadf SDL-1.2

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ALSA's idea of a "frame" is the same as SDL's idea of a "sample". The frame is a single sample on a single channel, and we've defined the frames for each channel as being interleaved.
author Sam Lantinga <slouken@libsdl.org>
date Tue, 13 Oct 2009 09:35:37 +0000
parents a24454ed4ac4
children 55717a755897
comparison
equal deleted inserted replaced
4331:a24454ed4ac4 4332:67e799ffcadf
304 304
305 305
306 static void ALSA_PlayAudio(_THIS) 306 static void ALSA_PlayAudio(_THIS)
307 { 307 {
308 int status; 308 int status;
309 snd_pcm_uframes_t samps_left; 309 snd_pcm_uframes_t frames_left;
310 const Uint8 *sample_buf = (const Uint8 *) mixbuf; 310 const Uint8 *sample_buf = (const Uint8 *) mixbuf;
311 const int sample_size = ((int) (this->spec.format & 0xFF)) / 8; 311 const int sample_size = ((int) (this->spec.format & 0xFF)) / 8;
312 312
313 swizzle_alsa_channels(this); 313 swizzle_alsa_channels(this);
314 314
315 samps_left = ((snd_pcm_uframes_t) this->spec.samples); 315 frames_left = ((snd_pcm_uframes_t) this->spec.samples);
316 316
317 while ( samps_left > 0 ) { 317 while ( frames_left > 0 ) {
318 status = SDL_NAME(snd_pcm_writei)(pcm_handle, sample_buf, samps_left); 318 status = SDL_NAME(snd_pcm_writei)(pcm_handle, sample_buf, frames_left);
319 if ( status < 0 ) { 319 if ( status < 0 ) {
320 if ( status == -EAGAIN ) { 320 if ( status == -EAGAIN ) {
321 SDL_Delay(1); 321 SDL_Delay(1);
322 continue; 322 continue;
323 } 323 }
336 return; 336 return;
337 } 337 }
338 continue; 338 continue;
339 } 339 }
340 sample_buf += status * sample_size; 340 sample_buf += status * sample_size;
341 samps_left -= status; 341 frames_left -= status;
342 } 342 }
343 } 343 }
344 344
345 static Uint8 *ALSA_GetAudioBuf(_THIS) 345 static Uint8 *ALSA_GetAudioBuf(_THIS)
346 { 346 {