X-Git-Url: https://git.sesse.net/?p=cubemap;a=blobdiff_plain;f=server.cpp;h=e99dbeaa89b311788a9c0fc4eb132a667db3f5b1;hp=a418d1c660d409b0ea85162696f9a33de01dc330;hb=52da76a04e309618da85197846b91ea27d36055d;hpb=52d37b2815f4b144fbac899b7f9548353a6fbe3c

diff --git a/server.cpp b/server.cpp
index a418d1c..e99dbea 100644
--- a/server.cpp
+++ b/server.cpp
@@ -469,21 +469,45 @@ sending_header_or_error_again:
 			return;
 		}
 
-		// Start sending from the first keyframe we get. In other
-		// words, we won't send any of the backlog, but we'll start
-		// sending immediately as we get the next keyframe block.
-		// This is postcondition #3.
+		Stream *stream = client->stream;
 		if (client->stream_pos == size_t(-2)) {
+			// Start sending from the beginning of the backlog.
 			client->stream_pos = std::min<size_t>(
-			    client->stream->bytes_received - client->stream->backlog_size,
+			    stream->bytes_received - stream->backlog_size,
 			    0);
 			client->state = Client::SENDING_DATA;
-		} else {
-			client->stream_pos = client->stream->bytes_received;
+			goto sending_data;
+		} else if (stream->prebuffering_bytes == 0) {
+			// Start sending from the first keyframe we get. In other
+			// words, we won't send any of the backlog, but we'll start
+			// sending immediately as we get the next keyframe block.
+			// Note that this is functionally identical to the next if branch,
+			// except that we save a binary search.
+			client->stream_pos = stream->bytes_received;
 			client->state = Client::WAITING_FOR_KEYFRAME;
+		} else {
+			// We're not going to send anything to the client before we have
+			// N bytes. However, this wait might be boring; we can just as well
+			// use it to send older data if we have it. We use lower_bound()
+			// so that we are conservative and never add extra latency over just
+			// waiting (assuming CBR or nearly so); otherwise, we could want e.g.
+			// 100 kB prebuffer but end up sending a 10 MB GOP.
+			deque<size_t>::const_iterator starting_point_it =
+				lower_bound(stream->suitable_starting_points.begin(),
+					    stream->suitable_starting_points.end(),
+					    stream->bytes_received - stream->prebuffering_bytes);
+			if (starting_point_it == stream->suitable_starting_points.end()) {
+				// None found. Just put us at the end, and then wait for the
+				// first keyframe to appear.
+				client->stream_pos = stream->bytes_received;
+				client->state = Client::WAITING_FOR_KEYFRAME;
+			} else {
+				client->stream_pos = *starting_point_it;
+				client->state = Client::PREBUFFERING;
+				goto prebuffering;
+			}
 		}
-		client->stream->put_client_to_sleep(client);
-		return;
+		// Fall through.
 	}
 	case Client::WAITING_FOR_KEYFRAME: {
 		Stream *stream = client->stream;
@@ -500,6 +524,7 @@ sending_header_or_error_again:
 		// Fall through.
 	}
 	case Client::PREBUFFERING: {
+prebuffering:
 		Stream *stream = client->stream;
 		size_t bytes_to_send = stream->bytes_received - client->stream_pos;
 		assert(bytes_to_send <= stream->backlog_size);
@@ -513,6 +538,7 @@ sending_header_or_error_again:
 		// Fall through.
 	}
 	case Client::SENDING_DATA: {
+sending_data:
 		skip_lost_data(client);
 		Stream *stream = client->stream;