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audio: Added basic WAVE_FORMAT_EXTENSIBLE support to .wav loader.

This is just enough to get you through a file that just used the extended
header for float or int data. It doesn't handle all the other things that
you expect from this header, like 24-bit samples inside a 32-bit container
or speaker masks.
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icculus committed Feb 17, 2017
1 parent 4a0b287 commit e8677a1bd2f3b277503c5e1d1dab6df56f3744aa
Showing with 33 additions and 0 deletions.
  1. +23 −0 src/audio/SDL_wave.c
  2. +10 −0 src/audio/SDL_wave.h
@@ -403,6 +403,10 @@ IMA_ADPCM_decode(Uint8 ** audio_buf, Uint32 * audio_len)
return (0);
}

/* GUIDs that are used by WAVE_FORMAT_EXTENSIBLE */
static const Uint8 extensible_pcm_guid[16] = { 1, 0, 0, 0, 0, 0, 16, 0, 128, 0, 0, 170, 0, 56, 155, 113 };
static const Uint8 extensible_ieee_guid[16] = { 3, 0, 0, 0, 0, 0, 16, 0, 128, 0, 0, 170, 0, 56, 155, 113 };

SDL_AudioSpec *
SDL_LoadWAV_RW(SDL_RWops * src, int freesrc,
SDL_AudioSpec * spec, Uint8 ** audio_buf, Uint32 * audio_len)
@@ -421,6 +425,7 @@ SDL_LoadWAV_RW(SDL_RWops * src, int freesrc,

/* FMT chunk */
WaveFMT *format = NULL;
WaveExtensibleFMT *ext = NULL;

SDL_zero(chunk);

@@ -494,6 +499,24 @@ SDL_LoadWAV_RW(SDL_RWops * src, int freesrc,
}
IMA_ADPCM_encoded = 1;
break;
case EXTENSIBLE_CODE:
/* note that this ignores channel masks, smaller valid bit counts
inside a larger container, and most subtypes. This is just enough
to get things that didn't really _need_ WAVE_FORMAT_EXTENSIBLE
to be useful working when they use this format flag. */
ext = (WaveExtensibleFMT *) format;
if (SDL_SwapLE16(ext->size) < 22) {
SDL_SetError("bogus extended .wav header");
was_error = 1;
goto done;
}
if (SDL_memcmp(ext->subformat, extensible_pcm_guid, 16) == 0) {
break; /* cool. */
} else if (SDL_memcmp(ext->subformat, extensible_ieee_guid, 16) == 0) {
IEEE_float_encoded = 1;
break;
}
break;
case MP3_CODE:
SDL_SetError("MPEG Layer 3 data not supported");
was_error = 1;
@@ -38,6 +38,7 @@
#define IEEE_FLOAT_CODE 0x0003
#define IMA_ADPCM_CODE 0x0011
#define MP3_CODE 0x0055
#define EXTENSIBLE_CODE 0xFFFE
#define WAVE_MONO 1
#define WAVE_STEREO 2

@@ -64,4 +65,13 @@ typedef struct Chunk
Uint8 *data;
} Chunk;

typedef struct WaveExtensibleFMT
{
WaveFMT format;
Uint16 size;
Uint16 validbits;
Uint32 channelmask;
Uint8 subformat[16]; /* a GUID. */
} WaveExtensibleFMT;

/* vi: set ts=4 sw=4 expandtab: */

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