[pulseaudio-discuss] [PATCH 2/2] bluetooth: Fix timing to count based on decoded data

[James Bunton]

Currently the latency information is being updated based on the encoded
SBC data instead of the decoded PCM data. Fixing this required moving
the timing update to be after the packet has been decoded.
---

> The read_index update is still not quite in the right place.
> sbc_decode() is called in a loop, and if it fails at any iteration,
> then read_index should not be updated. So, the update should happen
> after the loop.
I have updated the code to save the decoded byte count into a temporary
variable which is then used to update read_index.

Please let me know if anything else needs to be changed :)

Thanks!

 src/modules/bluetooth/module-bluez4-device.c |   12 +++++++-----
 src/modules/bluetooth/module-bluez5-device.c |   12 +++++++-----
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/src/modules/bluetooth/module-bluez4-device.c b/src/modules/bluetooth/module-bluez4-device.c
index 90b1bcd..c70e4a6 100644
--- a/src/modules/bluetooth/module-bluez4-device.c
+++ b/src/modules/bluetooth/module-bluez4-device.c
@@ -881,6 +881,7 @@ static int a2dp_process_push(struct userdata *u) {
         void *d;
         ssize_t l;
         size_t to_write, to_decode;
+        size_t total_written = 0;
 
         a2dp_prepare_buffer(u);
 
@@ -907,17 +908,12 @@ static int a2dp_process_push(struct userdata *u) {
 
         pa_assert((size_t) l <= a2dp->buffer_size);
 
-        u->read_index += (uint64_t) l;
-
         /* TODO: get timestamp from rtp */
         if (!found_tstamp) {
             /* pa_log_warn("Couldn't find SO_TIMESTAMP data in auxiliary recvmsg() data!"); */
             tstamp = pa_rtclock_now();
         }
 
-        pa_smoother_put(u->read_smoother, tstamp, pa_bytes_to_usec(u->read_index, &u->sample_spec));
-        pa_smoother_resume(u->read_smoother, tstamp, true);
-
         p = (uint8_t*) a2dp->buffer + sizeof(*header) + sizeof(*payload);
         to_decode = l - sizeof(*header) - sizeof(*payload);
 
@@ -943,6 +939,8 @@ static int a2dp_process_push(struct userdata *u) {
 /*             pa_log_debug("SBC: decoded: %lu; written: %lu", (unsigned long) decoded, (unsigned long) written); */
 /*             pa_log_debug("SBC: frame_length: %lu; codesize: %lu", (unsigned long) a2dp->frame_length, (unsigned long) a2dp->codesize); */
 
+            total_written += written;
+
             /* Reset frame length, it can be changed due to bitpool change */
             a2dp->frame_length = sbc_get_frame_length(&a2dp->sbc);
 
@@ -958,6 +956,10 @@ static int a2dp_process_push(struct userdata *u) {
             to_write -= written;
         }
 
+        u->read_index += (uint64_t) total_written;
+        pa_smoother_put(u->read_smoother, tstamp, pa_bytes_to_usec(u->read_index, &u->sample_spec));
+        pa_smoother_resume(u->read_smoother, tstamp, true);
+
         memchunk.length -= to_write;
 
         pa_memblock_release(memchunk.memblock);
diff --git a/src/modules/bluetooth/module-bluez5-device.c b/src/modules/bluetooth/module-bluez5-device.c
index 61723f8..857a972 100644
--- a/src/modules/bluetooth/module-bluez5-device.c
+++ b/src/modules/bluetooth/module-bluez5-device.c
@@ -402,6 +402,7 @@ static int a2dp_process_push(struct userdata *u) {
         void *d;
         ssize_t l;
         size_t to_write, to_decode;
+        size_t total_written = 0;
 
         a2dp_prepare_buffer(u);
 
@@ -428,17 +429,12 @@ static int a2dp_process_push(struct userdata *u) {
 
         pa_assert((size_t) l <= sbc_info->buffer_size);
 
-        u->read_index += (uint64_t) l;
-
         /* TODO: get timestamp from rtp */
         if (!found_tstamp) {
             /* pa_log_warn("Couldn't find SO_TIMESTAMP data in auxiliary recvmsg() data!"); */
             tstamp = pa_rtclock_now();
         }
 
-        pa_smoother_put(u->read_smoother, tstamp, pa_bytes_to_usec(u->read_index, &u->sample_spec));
-        pa_smoother_resume(u->read_smoother, tstamp, true);
-
         p = (uint8_t*) sbc_info->buffer + sizeof(*header) + sizeof(*payload);
         to_decode = l - sizeof(*header) - sizeof(*payload);
 
@@ -461,6 +457,8 @@ static int a2dp_process_push(struct userdata *u) {
                 return 0;
             }
 
+            total_written += written;
+
             /* Reset frame length, it can be changed due to bitpool change */
             sbc_info->frame_length = sbc_get_frame_length(&sbc_info->sbc);
 
@@ -476,6 +474,10 @@ static int a2dp_process_push(struct userdata *u) {
             to_write -= written;
         }
 
+        u->read_index += (uint64_t) total_written;
+        pa_smoother_put(u->read_smoother, tstamp, pa_bytes_to_usec(u->read_index, &u->sample_spec));
+        pa_smoother_resume(u->read_smoother, tstamp, true);
+
         memchunk.length -= to_write;
 
         pa_memblock_release(memchunk.memblock);
-- 
1.7.9.5