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dsp: Implemented audio capture support.

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icculus committed Aug 7, 2016
1 parent a0ff255 commit df4985e20758e5df5142d305ea23400ced39e590
Showing with 38 additions and 11 deletions.
  1. +38 −11 src/audio/dsp/SDL_dspaudio.c
@@ -107,9 +107,8 @@ DSP_OpenDevice(_THIS, void *handle, const char *devname, int iscapture)
if (this->hidden->audio_fd < 0) {
return SDL_SetError("Couldn't open %s: %s", devname, strerror(errno));
}
this->hidden->mixbuf = NULL;

/* Make the file descriptor use blocking writes with fcntl() */
/* Make the file descriptor use blocking i/o with fcntl() */
{
long ctlflags;
ctlflags = fcntl(this->hidden->audio_fd, F_GETFL);
@@ -236,12 +235,14 @@ DSP_OpenDevice(_THIS, void *handle, const char *devname, int iscapture)
#endif

/* Allocate mixing buffer */
this->hidden->mixlen = this->spec.size;
this->hidden->mixbuf = (Uint8 *) SDL_malloc(this->hidden->mixlen);
if (this->hidden->mixbuf == NULL) {
return SDL_OutOfMemory();
if (!iscapture) {
this->hidden->mixlen = this->spec.size;
this->hidden->mixbuf = (Uint8 *) SDL_malloc(this->hidden->mixlen);
if (this->hidden->mixbuf == NULL) {
return SDL_OutOfMemory();
}
SDL_memset(this->hidden->mixbuf, this->spec.silence, this->spec.size);
}
SDL_memset(this->hidden->mixbuf, this->spec.silence, this->spec.size);

/* We're ready to rock and roll. :-) */
return 0;
@@ -251,14 +252,13 @@ DSP_OpenDevice(_THIS, void *handle, const char *devname, int iscapture)
static void
DSP_PlayDevice(_THIS)
{
const Uint8 *mixbuf = this->hidden->mixbuf;
const int mixlen = this->hidden->mixlen;
if (write(this->hidden->audio_fd, mixbuf, mixlen) == -1) {
struct SDL_PrivateAudioData *h = this->hidden;
if (write(h->audio_fd, h->mixbuf, h->mixlen) == -1) {
perror("Audio write");
SDL_OpenedAudioDeviceDisconnected(this);
}
#ifdef DEBUG_AUDIO
fprintf(stderr, "Wrote %d bytes of audio data\n", mixlen);
fprintf(stderr, "Wrote %d bytes of audio data\n", h->mixlen);
#endif
}

@@ -268,6 +268,30 @@ DSP_GetDeviceBuf(_THIS)
return (this->hidden->mixbuf);
}

static int
DSP_CaptureFromDevice(_THIS, void *buffer, int buflen)
{
return (int) read(this->hidden->audio_fd, buffer, buflen);
}

static void
DSP_FlushCapture(_THIS)
{
struct SDL_PrivateAudioData *h = this->hidden;
audio_buf_info info;
if (ioctl(h->audio_fd, SNDCTL_DSP_GETISPACE, &info) == 0) {
while (info.bytes > 0) {
char buf[512];
const size_t len = SDL_min(sizeof (buf), info.bytes);
const ssize_t br = read(h->audio_fd, buf, len);
if (br <= 0) {
break;
}
info.bytes -= br;
}
}
}

static int
DSP_Init(SDL_AudioDriverImpl * impl)
{
@@ -277,8 +301,11 @@ DSP_Init(SDL_AudioDriverImpl * impl)
impl->PlayDevice = DSP_PlayDevice;
impl->GetDeviceBuf = DSP_GetDeviceBuf;
impl->CloseDevice = DSP_CloseDevice;
impl->CaptureFromDevice = DSP_CaptureFromDevice;
impl->FlushCapture = DSP_FlushCapture;

impl->AllowsArbitraryDeviceNames = 1;
impl->HasCaptureSupport = SDL_TRUE;

return 1; /* this audio target is available. */
}

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