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| author | Michael Giacomelli <giac2000@hotmail.com> | 2012-11-22 05:05:35 +0100 |
|---|---|---|
| committer | Michael Giacomelli <giac2000@hotmail.com> | 2012-11-22 05:18:00 +0100 |
| commit | d594b361330e6570b36ebd70c1a5aedfb0c76160 (patch) | |
| tree | 750f1ee831b91c04384b9603c431f7c1cce86ae5 | |
| parent | 3a39f77ed60df55abf1cf069a903d4665fb17cbc (diff) | |
| download | rockbox-d594b361330e6570b36ebd70c1a5aedfb0c76160.tar.gz rockbox-d594b361330e6570b36ebd70c1a5aedfb0c76160.zip | |
Add support for 16 bit 'half float' format PCM.
I'm not 100% sure that the rounding of denormals is correct. As compared to foobar2000,
some samples are off by +1 LSB. However, since I can't output 24 bit PCM easily with
rockbox, I'm not sure if this is due to a bug or just how rockbox rounds. In practice
I don't think it matters so I'm just going to commit this for now.
Change-Id: Ic0792fcb172e4369a5512d202121c2b918b36079
| -rw-r--r-- | lib/rbcodec/codecs/libpcm/ieee_float.c | 29 |
1 files changed, 28 insertions, 1 deletions
diff --git a/lib/rbcodec/codecs/libpcm/ieee_float.c b/lib/rbcodec/codecs/libpcm/ieee_float.c index 639390bcd5..97a7fcecd4 100644 --- a/lib/rbcodec/codecs/libpcm/ieee_float.c +++ b/lib/rbcodec/codecs/libpcm/ieee_float.c @@ -38,7 +38,7 @@ static bool set_format(struct pcm_format *format) return false; } - if (fmt->bitspersample != 32 && fmt->bitspersample != 64) + if (fmt->bitspersample != 16 && fmt->bitspersample != 32 && fmt->bitspersample != 64) { DEBUGF("CODEC_ERROR: ieee float must be 32 or 64 bitspersample: %d\n", fmt->bitspersample); @@ -114,6 +114,33 @@ static int decode(const uint8_t *inbuf, size_t inbufsize, } *outbufsize = inbufsize >> 2; } + else if (fmt->bitspersample == 16) + { + for (i = 0; i < inbufsize; i += 2) + { + pcm = inbuf[0]|((inbuf[1]&0x03)<<8); + exp = ((inbuf[1]&0x7c)>>2)-15; + sgn = (inbuf[1] & 0x80)>>7; + + if(exp == -15) + pcm =0; + else + { + pcm+=1<<10; + exp+=2; /*shift by 2 for rockbox fixed format*/ + if(exp>=0) + pcm <<= (exp); + else + pcm >>= (-exp); + + if (sgn) + pcm = -pcm; + } + outbuf[i/2] = pcm; + inbuf += 2; + } + *outbufsize = inbufsize >> 1; + } else { for (i = 0; i < inbufsize; i += 8) |