Commit 55fcca5b authored by Rémi Denis-Courmont's avatar Rémi Denis-Courmont
Browse files

Decoder for IEC61119 DAT12 (VLC_CODEC_DAT12)

This is the 12-bits logarithmic found on digital magnetic tapes,
also known at MIME audio/DAT12 (IETF RFC3190).
parent 1b7ec33b
......@@ -170,6 +170,7 @@ static const int16_t alawtos16[256] =
static void DecodeAlaw( void *, const uint8_t *, unsigned );
static void DecodeUlaw( void *, const uint8_t *, unsigned );
static void DecodeS20B( void *, const uint8_t *, unsigned );
static void DecodeDAT12( void *, const uint8_t *, unsigned );
/*****************************************************************************
* DecoderOpen: probe the decoder and return score
......@@ -192,6 +193,7 @@ static int DecoderOpen( vlc_object_t *p_this )
case VLC_CODEC_ALAW:
case VLC_CODEC_MULAW:
case VLC_CODEC_DAT12:
case VLC_CODEC_F64L:
case VLC_CODEC_F64B:
......@@ -274,6 +276,13 @@ static int DecoderOpen( vlc_object_t *p_this )
p_dec->fmt_out.i_codec = p_dec->fmt_in.i_codec;
p_dec->fmt_in.audio.i_bitspersample = 16;
}
else if( p_dec->fmt_in.i_codec == VLC_CODEC_DAT12 )
{
p_dec->fmt_out.i_codec = VLC_CODEC_S16N;
p_dec->fmt_out.audio.i_bitspersample = 16;
p_sys->decode = DecodeDAT12;
p_dec->fmt_in.audio.i_bitspersample = 12;
}
else if( p_dec->fmt_in.i_codec == VLC_CODEC_S8 ||
p_dec->fmt_in.i_codec == VLC_CODEC_U8 )
{
......@@ -426,6 +435,34 @@ static void DecodeS20B( void *outp, const uint8_t *in, unsigned samples )
*(out++) = ((U16_AT(in) << 16) | (in[2] << 8)) & ~0xFFF;
}
static int16_t dat12tos16( uint16_t y )
{
static const uint16_t diff[16] = {
0x0000, 0x0000, 0x0100, 0x0200, 0x0300, 0x0400, 0x0500, 0x0600,
0x0A00, 0x0B00, 0x0C00, 0x0D00, 0x0E00, 0x0F00, 0x1000, 0x1000 };
static const uint8_t shift[16] = {
0, 0, 1, 2, 3, 4, 5, 6, 6, 5, 4, 3, 2, 1, 0, 0 };
int d = y >> 8;
return (y - diff[d]) << shift[d];
}
static void DecodeDAT12( void *outp, const uint8_t *in, unsigned samples )
{
int32_t *out = outp;
while( samples >= 2 )
{
*(out++) = dat12tos16(U16_AT(in) >> 4);
*(out++) = dat12tos16(U16_AT(in + 1) & ~0xF000);
in += 3;
samples -= 2;
}
if( samples )
*(out++) = dat12tos16(U16_AT(in) >> 4);
}
/*****************************************************************************
* DecoderClose: decoder destruction
*****************************************************************************/
......
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