Merge "A2DP: SBC encoding counter errata" (bb6d57f3) · Commits · e / os / android_packages_modules_Bluetooth

system/stack/a2dp/a2dp_sbc_encoder.cc

+26 −11

Original line number	Diff line number	Diff line
		@@ -22,6 +22,7 @@
		#include "a2dp_sbc_encoder.h"

		#include <limits.h>
		#include <math.h>
		#include <stdio.h>
		#include <string.h>

		@@ -71,8 +72,8 @@ typedef struct {
		int32_t aa_feed_counter;
		int32_t aa_feed_residue;
		uint32_t counter;
		uint32_t bytes_per_tick; /* pcm bytes read each media task tick */
		uint64_t last_frame_us;
		uint32_t bytes_per_tick; // pcm bytes read each media task tick
		uint64_t last_frame_timestamp_100ns; // values in 1/10 microseconds
		} tA2DP_SBC_FEEDING_STATE;

		typedef struct {
		@@ -429,15 +430,29 @@ static void a2dp_sbc_get_num_frame_iteration(uint8_t* num_of_iterations,
		a2dp_sbc_encoder_cb.feeding_params.bits_per_sample / 8;
		LOG_VERBOSE("%s: pcm_bytes_per_frame %u", __func__, pcm_bytes_per_frame);

		uint32_t us_this_tick = A2DP_SBC_ENCODER_INTERVAL_MS * 1000;
		uint64_t now_us = timestamp_us;
		if (a2dp_sbc_encoder_cb.feeding_state.last_frame_us != 0)
		us_this_tick = (now_us - a2dp_sbc_encoder_cb.feeding_state.last_frame_us);
		a2dp_sbc_encoder_cb.feeding_state.last_frame_us = now_us;

		a2dp_sbc_encoder_cb.feeding_state.counter +=
		a2dp_sbc_encoder_cb.feeding_state.bytes_per_tick * us_this_tick /
		(A2DP_SBC_ENCODER_INTERVAL_MS * 1000);
		uint32_t hecto_ns_this_tick = A2DP_SBC_ENCODER_INTERVAL_MS * 10000;
		uint64_t* last_100ns =
		&a2dp_sbc_encoder_cb.feeding_state.last_frame_timestamp_100ns;
		uint64_t now_100ns = timestamp_us * 10;
		if (*last_100ns != 0) {
		hecto_ns_this_tick = (now_100ns - *last_100ns);
		}
		*last_100ns = now_100ns;

		uint32_t bytes_this_tick = a2dp_sbc_encoder_cb.feeding_state.bytes_per_tick *
		hecto_ns_this_tick /
		(A2DP_SBC_ENCODER_INTERVAL_MS * 10000);
		a2dp_sbc_encoder_cb.feeding_state.counter += bytes_this_tick;
		// Without this erratum, there was a three microseocnd shift per tick which
		// would cause one SBC frame mismatched after every 20 seconds
		uint32_t erratum_100ns =
		ceil(1.0f * A2DP_SBC_ENCODER_INTERVAL_MS * 10000 * bytes_this_tick /
		a2dp_sbc_encoder_cb.feeding_state.bytes_per_tick);
		if (erratum_100ns < hecto_ns_this_tick) {
		LOG_VERBOSE("%s: hecto_ns_this_tick=%d, bytes=%d, erratum_100ns=%d",
		__func__, hecto_ns_this_tick, bytes_this_tick, erratum_100ns);
		*last_100ns -= hecto_ns_this_tick - erratum_100ns;
		}

		/* Calculate the number of frames pending for this media tick */
		projected_nof =