From b30bf121d20dd2bacf4577f52f9bae4ff86bc2c8 Mon Sep 17 00:00:00 2001 From: Wim Taymans Date: Tue, 31 Aug 2010 18:04:33 +0200 Subject: echo-cancel: keep frame_size a power of 2 The speex echo canceler prefers a power of 2 for the frame size. Round down the ideal frame_size to the nearest power of two. This makes sure we don't create more than the requested frame_size_ms latency while still providing a power of 2 to the speex echo canceller. --- src/modules/module-echo-cancel.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/src/modules/module-echo-cancel.c b/src/modules/module-echo-cancel.c index 4d44bf73..d6c2ca14 100644 --- a/src/modules/module-echo-cancel.c +++ b/src/modules/module-echo-cancel.c @@ -1269,7 +1269,7 @@ int pa__init(pa_module*m) { pa_source_new_data source_data; pa_sink_new_data sink_data; pa_memchunk silence; - int framelen, rate; + int framelen, rate, y; uint32_t frame_size_ms, filter_size_ms; uint32_t adjust_time_sec; @@ -1323,6 +1323,13 @@ int pa__init(pa_module*m) { u->frame_size_ms = frame_size_ms; rate = ss.rate; framelen = (rate * frame_size_ms) / 1000; + + /* framelen should be a power of 2, round down to nearest power of two */ + y = 1 << ((8 * sizeof (int)) - 2); + while (y > framelen) + y >>= 1; + framelen = y; + u->blocksize = framelen * pa_frame_size (&ss); pa_log_debug ("Using framelen %d, blocksize %lld, channels %d, rate %d", framelen, (long long) u->blocksize, ss.channels, ss.rate); -- cgit v1.2.3