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transmit.cpp: compute packet rate in separate func

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This commit is contained in:
Martin Pulec
2022-07-18 13:36:36 +02:00
parent 309973738f
commit 5be9d658e4
1 changed files with 31 additions and 24 deletions
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55
src/transmit.cpp
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@@ -545,6 +545,36 @@ static vector<int> get_packet_sizes(struct video_frame *frame, int substream, in
return ret;
}
/**
* Returns inter-packet interval in nanoseconds.
*/
static long
get_packet_rate(struct tx *tx, struct video_frame *frame, int substream, long packet_count)
{
if (tx->bitrate == RATE_UNLIMITED) {
return 0;
}
double time_for_frame = 1.0 / frame->fps / frame->tile_count;
double interval_between_pkts = time_for_frame / tx->mult_count / packet_count;
// use only 75% of the time - we less likely overshot the frame time and
// can minimize risk of swapping packets between 2 frames (out-of-order ones)
interval_between_pkts = interval_between_pkts * 0.75;
// prevent bitrate to be "too low", here 1 Mbps at minimum
interval_between_pkts = std::min<double>(interval_between_pkts, tx->mtu / 1000'000.0);
long long packet_rate_auto = interval_between_pkts * 1000'000'000LL;
if (tx->bitrate == RATE_AUTO) { // adaptive (spread packets to 75% frame time)
return packet_rate_auto;
}
long long int bitrate = tx->bitrate & ~RATE_FLAG_FIXED_RATE;
int avg_packet_size = frame->tiles[substream].data_len / packet_count;
long packet_rate = 1000'000'000LL * avg_packet_size * 8 / bitrate; // fixed rate
if ((tx->bitrate & RATE_FLAG_FIXED_RATE) == 0) { // adaptive capped rate
packet_rate = std::max<long long>(packet_rate, packet_rate_auto);
}
return packet_rate;
}
static void
tx_send_base(struct tx *tx, struct video_frame *frame, struct rtp *rtp_session,
uint32_t ts, int send_m,
@@ -610,30 +640,7 @@ tx_send_base(struct tx *tx, struct video_frame *frame, struct rtp *rtp_session,
vector<int> packet_sizes = get_packet_sizes(frame, substream, tx->mtu - hdrs_len);
long packet_count = packet_sizes.size() * (tx->fec_scheme == FEC_MULT ? tx->mult_count : 1);
long packet_rate;
if (tx->bitrate == RATE_UNLIMITED) {
packet_rate = 0;
} else {
double time_for_frame = 1.0 / frame->fps / frame->tile_count;
double interval_between_pkts = time_for_frame / tx->mult_count / packet_count;
// use only 75% of the time - we less likely overshot the frame time and
// can minimize risk of swapping packets between 2 frames (out-of-order ones)
interval_between_pkts = interval_between_pkts * 0.75;
// prevent bitrate to be "too low", here 1 Mbps at minimum
interval_between_pkts = std::min<double>(interval_between_pkts, tx->mtu / 1000000.0);
long long packet_rate_auto = interval_between_pkts * 1000ll * 1000 * 1000;
if (tx->bitrate == RATE_AUTO) { // adaptive (spread packets to 75% frame time)
packet_rate = packet_rate_auto;
} else { // bitrate given manually
long long int bitrate = tx->bitrate & ~RATE_FLAG_FIXED_RATE;
int avg_packet_size = tile->data_len / packet_count;
packet_rate = 1000ll * 1000 * 1000 * avg_packet_size * 8 / bitrate; // fixed rate
if ((tx->bitrate & RATE_FLAG_FIXED_RATE) == 0) { // adaptive capped rate
packet_rate = std::max<long long>(packet_rate, packet_rate_auto);
}
}
}
long packet_rate = get_packet_rate(tx, frame, substream, packet_count);
// initialize header array with values (except offset which is different among
// different packts)