當我編譯ALSA的pcm_min.c例如與來自ALSA的pcm_min.c示例的警告/錯誤。可能的問題?
gcc -Wall -lasound pcm_min.c -o pcm_min
一切都很好,但運行它,我得到預期的白噪聲,但我也得到這樣的警告/錯誤:
Short write (expected 16384, wrote 7616)
哪個來從最後一條if語句開始。
#include <alsa/asoundlib.h>
static char *device = "default"; /* playback device */
snd_output_t *output = NULL;
unsigned char buffer[16*1024]; /* some random data */
int main(void)
{
int err;
unsigned int i;
snd_pcm_t *handle;
snd_pcm_sframes_t frames;
for (i = 0; i < sizeof(buffer); i++)
buffer[i] = random() & 0xff;
if ((err = snd_pcm_open(&handle, device, SND_PCM_STREAM_PLAYBACK, 0)) < 0) {
printf("Playback open error: %s\n", snd_strerror(err));
exit(EXIT_FAILURE);
}
if ((err = snd_pcm_set_params(handle,
SND_PCM_FORMAT_U8,
SND_PCM_ACCESS_RW_INTERLEAVED,
1,
48000,
1,
500000)) < 0) { /* 0.5sec */
printf("Playback open error: %s\n", snd_strerror(err));
exit(EXIT_FAILURE);
}
for (i = 0; i < 16; i++) {
frames = snd_pcm_writei(handle, buffer, sizeof(buffer));
if (frames < 0)
frames = snd_pcm_recover(handle, frames, 0);
if (frames < 0) {
printf("snd_pcm_writei failed: %s\n", snd_strerror(err));
break;
}
if (frames > 0 && frames < (long)sizeof(buffer))
printf("Short write (expected %li, wrote %li)\n", (long)sizeof(buffer), frames);
}
snd_pcm_close(handle);
return 0;
}
有人可以看到爲什麼會發生此警告/錯誤嗎?
擁抱, 路易絲
我不明白你想讓我試試。你能解釋一下嗎? – Louise 2009-11-16 06:21:24
我編輯了我的答案,因爲你傳遞的是字節數而不是幀數。 – Gonzalo 2009-11-16 06:29:10
非常酷。現在我自己的實現不會崩潰=)但我仍然得到相同的警告/錯誤。順便說一句。如果我刪除for循環(當然還保留它的內容),怎麼會這樣,我聽不到任何聲音? – Louise 2009-11-16 06:48:34