Incorrect int-to-float conversion in the JACK output plugin

Using bitmeter, I found that xine's jack output suffers from the problem
mentioned at the bottom of bitmeter's home page.

"Although JACK itself works entirely with IEEE floating point values the
 conversion to and from analog audio uses integers, as do popular audio
 storage technologies like DAT and Red Book CDs. For correct operation JACK
 software which uses such integers should use the same conversion ratios as
 JACK itself. e.g. 16-bit samples should be divided by exactly 32768.

 A common mistake is to choose the value 32767 instead. You can't hear this,
 or see it with ordinary meters, but the bitmeter shows a clear signature for
 audio processed in this way. The 8th bit of the mantissa (counting the
 rightmost as the 0th) is orange, indicating that an unusually high
 percentage of samples have this bit set."

 (from http://users.ecs.soton.ac.uk/njl98r/code/audio/bitmeter/
  via Google cache)

2 files changed, 2 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index ef1e5753d..84c51e994 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -18,6 +18,7 @@ xine-lib (1.1.17) 2009-??-??
   * Allow reading of non-block-sized chunks from audio CDs.
   * Add a user agent & protocol hack ("qthttp://...") to allow direct
     viewing of Apple film trailers.
+  * Fixed int-to-float conversion in the JACK output plugin.
 
 xine-lib (1.1.16.3) 2009-04-03
   * Security fixes:
diff --git a/src/audio_out/audio_jack_out.c b/src/audio_out/audio_jack_out.c
index 10c58c774..cd7da67cd 100644
--- a/src/audio_out/audio_jack_out.c
+++ b/src/audio_out/audio_jack_out.c
@@ -163,7 +163,7 @@ static int write_buffer_16 (jack_driver_t *this, unsigned char *data, int len)
   for (i = 0; i < samples; i++) {
     /* Read in 16bits, write out floats */
     p_write = (float *) (&(this->buffer[write_pos]));
-    *p_write = ((float) (p_read[i])) / 32767.0f;
+    *p_write = ((float) (p_read[i])) / 32768.0f;
     write_pos = (write_pos + sizeof (float)) % BUFFSIZE;
   }
   this->write_pos = write_pos;