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Cleanups, fixes and enhancements by Torbj?rn Andersson.
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@icculus
icculus committed Nov 26, 2001
1 parent 9717f47 commit 31f5b08
Showing 1 changed file with 79 additions and 38 deletions.
117 changes: 79 additions & 38 deletions decoders/flac.c
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Expand Up @@ -79,10 +79,18 @@ typedef struct
SDL_RWops *rw;
Sound_Sample *sample;
Uint32 frame_size;
Uint8 metadata_found;
Uint8 is_flac;
} flac_t;


static void free_flac(flac_t *f)
{
FLAC__stream_decoder_finish(f->decoder);
FLAC__stream_decoder_delete(f->decoder);
free(f);
} /* free_flac */


static FLAC__StreamDecoderReadStatus FLAC_read_callback(
const FLAC__StreamDecoder *decoder, FLAC__byte buffer[],
unsigned int *bytes, void *client_data)
Expand Down Expand Up @@ -126,6 +134,7 @@ static FLAC__StreamDecoderWriteStatus FLAC_write_callback(
{
flac_t *f = (flac_t *) client_data;
Uint32 i, j;
Uint32 sample;
Uint8 *dst;

#if 0
Expand All @@ -140,19 +149,34 @@ static FLAC__StreamDecoderWriteStatus FLAC_write_callback(

dst = f->sample->buffer;

if (frame->header.bits_per_sample == 8)
/* If the sample is neither exactly 8-bit nor 16-bit, it will have to
* be converted. Unfortunately the buffer is read-only, so we either
* have to check for each sample, or make a copy of the buffer. I'm
* not sure which way is best, so I've arbitrarily picked the former.
*/
if (f->sample->actual.format == AUDIO_S8)
{
for (i = 0; i < frame->header.blocksize; i++)
for (j = 0; j < frame->header.channels; j++)
*dst++ = buffer[j][i] & 0x000000ff;
{
sample = buffer[j][i];
if (frame->header.bits_per_sample < 8)
sample <<= (8 - frame->header.bits_per_sample);
*dst++ = sample & 0x00ff;
} /* for */
} /* if */
else
{
for (i = 0; i < frame->header.blocksize; i++)
for (j = 0; j < frame->header.channels; j++)
{
*dst++ = (buffer[j][i] & 0x0000ff00) >> 8;
*dst++ = buffer[j][i] & 0x000000ff;
sample = buffer[j][i];
if (frame->header.bits_per_sample < 16)
sample <<= (16 - frame->header.bits_per_sample);
else if (frame->header.bits_per_sample > 16)
sample >>= (frame->header.bits_per_sample - 16);
*dst++ = (sample & 0xff00) >> 8;
*dst++ = sample & 0x00ff;
} /* for */
} /* else */

Expand All @@ -168,29 +192,21 @@ void FLAC_metadata_callback(

SNDDBG(("FLAC: Metadata callback.\n"));

/* There are several kinds of metadata, but STREAMINFO is the only
* one that always has to be there.
*/
if (metadata->type == FLAC__METADATA_TYPE_STREAMINFO)
{
SNDDBG(("FLAC: Metadata is streaminfo.\n"));
f->metadata_found = 1;

f->is_flac = 1;
f->sample->actual.channels = metadata->data.stream_info.channels;
f->sample->actual.rate = metadata->data.stream_info.sample_rate;

/* !!! FIXME: I believe bits_per_sample may be anywhere between
* 4 and 24. We can only handle 8 and 16 at present.
*/
switch (metadata->data.stream_info.bits_per_sample)
{
case 8:
f->sample->actual.format = AUDIO_S8;
break;
case 16:
f->sample->actual.format = AUDIO_S16MSB;
break;
default:
Sound_SetError("FLAC: Unsupported sample width.");
f->sample->actual.format = 0;
break;
} /* switch */
if (metadata->data.stream_info.bits_per_sample > 8)
f->sample->actual.format = AUDIO_S16MSB;
else
f->sample->actual.format = AUDIO_S8;
} /* if */
} /* FLAC_metadata_callback */

Expand All @@ -201,6 +217,7 @@ void FLAC_error_callback(
{
flac_t *f = (flac_t *) client_data;

/* !!! FIXME: Is every error really fatal? I don't know... */
Sound_SetError(FLAC__StreamDecoderErrorStatusString[status]);
f->sample->flags |= SOUND_SAMPLEFLAG_ERROR;
} /* FLAC_error_callback */
Expand All @@ -224,6 +241,7 @@ static int FLAC_open(Sound_Sample *sample, const char *ext)
SDL_RWops *rw = internal->rw;
FLAC__StreamDecoder *decoder;
flac_t *f;
int i;

f = (flac_t *) malloc(sizeof (flac_t));
BAIL_IF_MACRO(f == NULL, ERR_OUT_OF_MEMORY, 0);
Expand All @@ -245,22 +263,47 @@ static int FLAC_open(Sound_Sample *sample, const char *ext)
f->rw = internal->rw;
f->sample = sample;
f->decoder = decoder;

FLAC__stream_decoder_init(decoder);
internal->decoder_private = f;

f->metadata_found = 0;
f->sample->actual.format = 0;
FLAC__stream_decoder_process_metadata(decoder);
f->is_flac = 0;

if (f->sample->actual.format == 0)
#if 0
/* !!! FIXME:
*
* It should be possible to play a FLAC stream starting at any frame,
* but we can only do that if we know for sure that it is a FLAC
* stream. Otherwise we have to check for metadata, and then we need
* the entire stream, from the beginning.
*
* But getting this to work right seems to be an enormous pain in the
* butt for what is, at the moment, a very small gain. Maybe later.
*/
for (i = 0; extensions_flac[i] != NULL; i++)
if (__Sound_strcasecmp(ext, extensions_flac[i]) == 0)
{
f->is_flac = 1;
break;
} /* if */
#endif

internal->decoder_private = f;
FLAC__stream_decoder_init(decoder);

/* If we are not sure this is a FLAC stream, check for the STREAMINFO
* metadata block. If not, we'd have to peek at the first audio frame
* and get the sound format from there but, as stated above, that is
* not yet implemented.
*/
if (!f->is_flac)
{
if (f->metadata_found == 0)
Sound_SetError("FLAC: No metadata found.");
FLAC__stream_decoder_finish(decoder);
FLAC__stream_decoder_delete(decoder);
free(f);
return(0);
FLAC__stream_decoder_process_metadata(decoder);

/* Still not FLAC? Give up. */
if (!f->is_flac)
{
Sound_SetError("FLAC: No metadata found. Not a FLAC stream?");
free_flac(f);
return(0);
} /* if */
} /* if */

SNDDBG(("FLAC: Accepting data stream.\n"));
Expand All @@ -275,9 +318,7 @@ static void FLAC_close(Sound_Sample *sample)
Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
flac_t *f = (flac_t *) internal->decoder_private;

FLAC__stream_decoder_finish(f->decoder);
FLAC__stream_decoder_delete(f->decoder);
free(f);
free_flac(f);
} /* FLAC_close */


Expand Down

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