SDL_sound_CoreAudio: decoders/flac.c comparison

comparison decoders/flac.c @ 166:d8904267d23c

Cleanups, fixes and enhancements by Torbj�rn Andersson.

author	Ryan C. Gordon <icculus@icculus.org>
date	Mon, 26 Nov 2001 04:32:55 +0000
parents	77482005beb6
children	3849438b735e

comparison

equal deleted inserted replaced

-:9b26ed9eaf04
+:d8904267d23c
 {
 FLAC__StreamDecoder *decoder;
 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)
 const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame,
 const FLAC__int32 *buffer[], void *client_data)
 {
 flac_t *f = (flac_t *) client_data;
 Uint32 i, j;
+Uint32 sample;
 Uint8 *dst;
 #if 0
 SNDDBG(("FLAC: Write callback.\n"));
 #endif
 if (f->frame_size > f->sample->buffer_size)
 Sound_SetBufferSize(f->sample, f->frame_size);
 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
-for (i = 0; i < frame->header.blocksize; i++)
+* have to check for each sample, or make a copy of the buffer. I'm
-for (j = 0; j < frame->header.channels; j++)
+* not sure which way is best, so I've arbitrarily picked the former.
-*dst++ = buffer[j][i] & 0x000000ff;
+*/
-} /* if */
+if (f->sample->actual.format == AUDIO_S8)
-else
 {
 for (i = 0; i < frame->header.blocksize; i++)
 for (j = 0; j < frame->header.channels; j++)
 {
-*dst++ = (buffer[j][i] & 0x0000ff00) >> 8;
+sample = buffer[j][i];
-*dst++ = buffer[j][i] & 0x000000ff;
+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++)
+{
+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 */
 return(FLAC__STREAM_DECODER_WRITE_CONTINUE);
 } /* FLAC_write_callback */
 {
 flac_t *f = (flac_t *) client_data;
 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
+if (metadata->data.stream_info.bits_per_sample > 8)
-* 4 and 24. We can only handle 8 and 16 at present.
+f->sample->actual.format = AUDIO_S16MSB;
-*/
+else
-switch (metadata->data.stream_info.bits_per_sample)
+f->sample->actual.format = AUDIO_S8;
-{
-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 */
 } /* FLAC_metadata_callback */
 void FLAC_error_callback(
 const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status,
 void *client_data)
 {
 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 */
 {
 Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
 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);
 decoder = FLAC__stream_decoder_new();
 FLAC__stream_decoder_set_client_data(decoder, f);
 f->rw = internal->rw;
 f->sample = sample;
 f->decoder = decoder;
+f->sample->actual.format = 0;
+f->is_flac = 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);
-internal->decoder_private = f;
+/* If we are not sure this is a FLAC stream, check for the STREAMINFO
-f->metadata_found = 0;
+* metadata block. If not, we'd have to peek at the first audio frame
-f->sample->actual.format = 0;
+* and get the sound format from there but, as stated above, that is
-FLAC__stream_decoder_process_metadata(decoder);
+* not yet implemented.
+*/
-if (f->sample->actual.format == 0)
+if (!f->is_flac)
 {
-if (f->metadata_found == 0)
+FLAC__stream_decoder_process_metadata(decoder);
-Sound_SetError("FLAC: No metadata found.");
-FLAC__stream_decoder_finish(decoder);
+/* Still not FLAC? Give up. */
-FLAC__stream_decoder_delete(decoder);
+if (!f->is_flac)
-free(f);
+{
-return(0);
+Sound_SetError("FLAC: No metadata found. Not a FLAC stream?");
+free_flac(f);
+return(0);
+} /* if */
 } /* if */
 SNDDBG(("FLAC: Accepting data stream.\n"));
 sample->flags = SOUND_SAMPLEFLAG_NONE;
 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);
+free_flac(f);
-FLAC__stream_decoder_delete(f->decoder);
-free(f);
 } /* FLAC_close */
 static Uint32 FLAC_read(Sound_Sample *sample)
 {

Mercurial > SDL_sound_CoreAudio

comparison decoders/flac.c @ 166:d8904267d23c