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  • 操作系统：Angstrom Linux 2012.12，内核 3.8.13 在 BeagleBone Black Rev A5B 上运行。
  • SDL：libsdl 1.2.0，sdl-config 1.2.15

我正在尝试使用 SDL 在 BeagleBone Black 上编写音调发生器。dummy但是，除非我使用驱动程序，否则 SDL 音频似乎不起作用。我正在使用以下代码尝试诊断 SDL_AudioOpen 问题：

#include <SDL/SDL.h>
#include <SDL/SDL_audio.h>
#include <iostream>

void audio_callback (void*, Uint8*, int) { }

void ReportError (const char *where, int status) {
  std::cerr << "SDL Error: " << where << " (" << status << ") "
            << SDL_GetError () << std::endl;
  exit (1);
}

void ReportEnv (const char *var) {
  const char *driver = getenv (var);
  if (NULL == driver)
    std::cerr << var << " is null" << std::endl;
  else
    std::cerr << var << ": " << driver << std::endl;
}

int main (int argc, char **argv)
{ ReportEnv ("SDL_AUDIODRIVER");

  int ret = SDL_Init (SDL_INIT_AUDIO);
  if (0 != ret)
    ReportError ("SDL_Init", ret);

  SDL_AudioSpec ds, obtained;
  ds . freq = 44100;
  ds . format = AUDIO_S16;
  ds . channels = 1;
  ds . samples = 1024;
  ds . callback = audio_callback;
  ds . userdata = NULL;

  ret = SDL_OpenAudio (&ds, &obtained);
  if (0 != ret)
    ReportError ("SDL_OpenAudio", ret);

  std::cout << "Success" << std::endl;

  return 0;
}

我得到以下结果：

% SDL_AUDIODRIVER=dummy ./simple
SDL_AUDIODRIVER: dummy
Success
% SDL_AUDIODRIVER=alsa ./simple
SDL_AUDIODRIVER: alsa
SDL Error: SDL_OpenAudio (-1) No available audio device
% SDL_AUDIODRIVER=disk ./simple
SDL_AUDIODRIVER: disk
SDL Error: SDL_OpenAudio (-1) No available audio device
%

aplay有效，所以似乎 ALSA 至少部分配置正确。

我错过了什么？似乎disk司机应该在所有情况下工作。

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0 回答 0