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added declicking xfade in audio_diskstream for truly seamless transport looping

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git-svn-id: svn://localhost/ardour2/branches/2.0-ongoing@1932 d708f5d6-7413-0410-9779-e7cbd77b26cf
This commit is contained in:
Jesse Chappell 2007-05-31 03:32:29 +00:00
parent 1fedefc785
commit c967b91ddf
2 changed files with 35 additions and 4 deletions
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37
libs/ardour/audio_diskstream.cc
View file

@ -1001,6 +1001,8 @@ AudioDiskstream::read (Sample* buf, Sample* mixdown_buffer, float* gain_buffer,
nframes_t loop_start = 0;
nframes_t loop_length = 0;
nframes_t offset = 0;
nframes_t xfade_samples = 0;
Sample xfade_buf[128];
Location *loc = 0;
/* XXX we don't currently play loops in reverse. not sure why */
@ -1063,6 +1065,26 @@ AudioDiskstream::read (Sample* buf, Sample* mixdown_buffer, float* gain_buffer,
return -1;
}
// xfade loop boundary if appropriate
if (xfade_samples > 0) {
// just do a linear xfade for this short bit
xfade_samples = min(xfade_samples, this_read);
float delta = 1.0f / xfade_samples;
float scale = 0.0f;
Sample * tmpbuf = buf+offset;
for (size_t i=0; i < xfade_samples; ++i) {
*tmpbuf = (*tmpbuf * scale) + xfade_buf[i]*(1.0f - scale);
++tmpbuf;
scale += delta;
}
xfade_samples = 0;
}
_read_data_count = _playlist->read_data_count();
if (reversed) {
@ -1070,13 +1092,22 @@ AudioDiskstream::read (Sample* buf, Sample* mixdown_buffer, float* gain_buffer,
swap_by_ptr (buf, buf + this_read - 1);
} else {
start += this_read;
/* if we read to the end of the loop, go back to the beginning */
if (reloop) {
// read crossfade samples to apply to the next read
xfade_samples = min((nframes_t) 128, cnt-this_read);
if (audio_playlist()->read (xfade_buf, mixdown_buffer, gain_buffer, start, xfade_samples, channel) != xfade_samples) {
error << string_compose(_("AudioDiskstream %1: cannot read xfade samples %2 from playlist at frame %3"),
_id, xfade_samples,start) << endmsg;
memset(xfade_buf, 0, xfade_samples * sizeof(Sample)); // just in case
}
start = loop_start;
} else {
start += this_read;
}
}

2
libs/ardour/automation_event.cc
View file

@ -14,7 +14,7 @@
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <set>