static void sdl_audio_callback(void *opaque, Uint8 *stream, int len) { VideoState *is = opaque; int audio_size, len1, silence = 0; audio_callback_time = av_gettime_relative(); while (len > 0) { if (is->audio_buf_index >= is->audio_buf_size) { audio_size = audio_decode_frame(is); if (audio_size < 0) { /* if error, just output silence */ silence = 1; is->audio_buf_size = SDL_AUDIO_MIN_BUFFER_SIZE / is->audio_tgt.frame_size * is->audio_tgt.frame_size; } else { if (is->show_mode != SHOW_MODE_VIDEO) update_sample_display(is, (int16_t *)is->audio_buf, audio_size); is->audio_buf_size = audio_size; } is->audio_buf_index = 0; } len1 = is->audio_buf_size - is->audio_buf_index; if (len1 > len) len1 = len; if (!is->muted && !silence && is->audio_volume == SDL_MIX_MAXVOLUME) memcpy(stream, (uint8_t *)is->audio_buf + is->audio_buf_index, len1); else { memset(stream, 0, len1); if (!is->muted && !silence) SDL_MixAudio(stream, (uint8_t *)is->audio_buf + is->audio_buf_index, len1, is->audio_volume); } len -= len1; stream += len1; is->audio_buf_index += len1; } is->audio_write_buf_size = is->audio_buf_size - is->audio_buf_index; /* Let's assume the audio driver that is used by SDL has two periods. */ if (!isnan(is->audio_clock)) { set_clock_at(&is->audclk, is->audio_clock - (double)(2 * is->audio_hw_buf_size + is->audio_write_buf_size) / is->audio_tgt.bytes_per_sec, is->audio_clock_serial, audio_callback_time / 1000000.0); sync_clock_to_slave(&is->extclk, &is->audclk); } }
static void sdl_audio_callback(void *opaque, Uint8 *stream, int len) { VideoState *is = opaque; int audio_size, len1, silence = 0; audio_callback_time = av_gettime_relative(); while (len > 0) { if (is->audio_buf_index >= is->audio_buf_size) { audio_size = audio_decode_frame(is); if (audio_size < 0) {   silence = 1; is->audio_buf_size = SDL_AUDIO_MIN_BUFFER_SIZE / is->audio_tgt.frame_size * is->audio_tgt.frame_size; } else { if (is->show_mode != SHOW_MODE_VIDEO) update_sample_display(is, (int16_t *)is->audio_buf, audio_size); is->audio_buf_size = audio_size; } is->audio_buf_index = 0; } len1 = is->audio_buf_size - is->audio_buf_index; if (len1 > len) len1 = len; if (!is->muted && !silence && is->audio_volume == SDL_MIX_MAXVOLUME) memcpy(stream, (uint8_t *)is->audio_buf + is->audio_buf_index, len1); else { memset(stream, 0, len1); if (!is->muted && !silence) SDL_MixAudio(stream, (uint8_t *)is->audio_buf + is->audio_buf_index, len1, is->audio_volume); } len -= len1; stream += len1; is->audio_buf_index += len1; } is->audio_write_buf_size = is->audio_buf_size - is->audio_buf_index;   if (!isnan(is->audio_clock)) { set_clock_at(&is->audclk, is->audio_clock - (double)(2 * is->audio_hw_buf_size + is->audio_write_buf_size) / is->audio_tgt.bytes_per_sec, is->audio_clock_serial, audio_callback_time / 1000000.0); sync_clock_to_slave(&is->extclk, &is->audclk); } }