in RtpPacketizer add support for first packet reduction length
Bug: webrtc:9680
Change-Id: I68580a8a44cbbf932ed0b2448b31169b26df5044
Reviewed-on: https://webrtc-review.googlesource.com/98005
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24584}diff --git a/modules/rtp_rtcp/source/rtp_format.cc b/modules/rtp_rtcp/source/rtp_format.cc
index bddec73..030236c 100644
--- a/modules/rtp_rtcp/source/rtp_format.cc
+++ b/modules/rtp_rtcp/source/rtp_format.cc
@@ -65,11 +65,15 @@
std::vector<size_t> RtpPacketizer::SplitAboutEqually(
size_t payload_len,
const PayloadSizeLimits& limits) {
+ RTC_CHECK_GT(limits.max_payload_len, limits.first_packet_reduction_len);
RTC_CHECK_GT(limits.max_payload_len, limits.last_packet_reduction_len);
- // Last packet can be smaller. Pretend that it's the same size, but we must
- // write more payload to it.
- size_t total_bytes = payload_len + limits.last_packet_reduction_len;
+ // First and last packet of the frame can be smaller. Pretend that it's
+ // the same size, but we must write more payload to it.
+ // Assume frame fits in single packet if packet has extra space for sum
+ // of first and last packets reductions.
+ size_t total_bytes = payload_len + limits.first_packet_reduction_len +
+ limits.last_packet_reduction_len;
// Integer divisions with rounding up.
size_t num_packets_left =
(total_bytes + limits.max_payload_len - 1) / limits.max_payload_len;
@@ -79,12 +83,19 @@
std::vector<size_t> result;
result.reserve(num_packets_left);
+ bool first_packet = true;
while (remaining_data > 0) {
// Last num_larger_packets are 1 byte wider than the rest. Increase
// per-packet payload size when needed.
if (num_packets_left == num_larger_packets)
++bytes_per_packet;
size_t current_packet_bytes = bytes_per_packet;
+ if (first_packet) {
+ if (current_packet_bytes > limits.first_packet_reduction_len + 1)
+ current_packet_bytes -= limits.first_packet_reduction_len;
+ else
+ current_packet_bytes = 1;
+ }
if (current_packet_bytes > remaining_data) {
current_packet_bytes = remaining_data;
}
@@ -93,11 +104,11 @@
if (num_packets_left == 2 && current_packet_bytes == remaining_data) {
--current_packet_bytes;
}
-
result.push_back(current_packet_bytes);
remaining_data -= current_packet_bytes;
--num_packets_left;
+ first_packet = false;
}
return result;
diff --git a/modules/rtp_rtcp/source/rtp_format.h b/modules/rtp_rtcp/source/rtp_format.h
index f945d24..7a1f494 100644
--- a/modules/rtp_rtcp/source/rtp_format.h
+++ b/modules/rtp_rtcp/source/rtp_format.h
@@ -28,6 +28,7 @@
public:
struct PayloadSizeLimits {
size_t max_payload_len = 1200;
+ size_t first_packet_reduction_len = 0;
size_t last_packet_reduction_len = 0;
};
static std::unique_ptr<RtpPacketizer> Create(
diff --git a/modules/rtp_rtcp/source/rtp_format_unittest.cc b/modules/rtp_rtcp/source/rtp_format_unittest.cc
index 6b83432..8fb780e 100644
--- a/modules/rtp_rtcp/source/rtp_format_unittest.cc
+++ b/modules/rtp_rtcp/source/rtp_format_unittest.cc
@@ -21,6 +21,7 @@
using ::testing::ElementsAre;
using ::testing::Le;
+using ::testing::Gt;
using ::testing::Each;
using ::testing::IsEmpty;
using ::testing::Not;
@@ -67,6 +68,20 @@
}
TEST(RtpPacketizerSplitAboutEqually,
+ AllPacketsAreEqualRespectsFirstPacketReduction) {
+ RtpPacketizer::PayloadSizeLimits limits;
+ limits.max_payload_len = 5;
+ limits.first_packet_reduction_len = 2;
+
+ std::vector<size_t> payload_sizes =
+ RtpPacketizer::SplitAboutEqually(13, limits);
+
+ ASSERT_THAT(payload_sizes, Not(IsEmpty()));
+ EXPECT_EQ(payload_sizes.front() + limits.first_packet_reduction_len,
+ limits.max_payload_len);
+}
+
+TEST(RtpPacketizerSplitAboutEqually,
AllPacketsAreEqualRespectsLastPacketReductionLength) {
RtpPacketizer::PayloadSizeLimits limits;
limits.max_payload_len = 5;
@@ -115,7 +130,8 @@
EXPECT_THAT(Sum(payload_sizes), 28);
}
-TEST(RtpPacketizerVideoGeneric, SomePacketsAreSmallerRespectsMaxPayloadSize) {
+TEST(RtpPacketizerSplitAboutEqually,
+ SomePacketsAreSmallerRespectsMaxPayloadSize) {
RtpPacketizer::PayloadSizeLimits limits;
limits.max_payload_len = 7;
limits.last_packet_reduction_len = 5;
@@ -126,7 +142,20 @@
EXPECT_THAT(payload_sizes, Each(Le(limits.max_payload_len)));
}
-TEST(RtpPacketizerVideoGeneric,
+TEST(RtpPacketizerSplitAboutEqually,
+ SomePacketsAreSmallerRespectsFirstPacketReduction) {
+ RtpPacketizer::PayloadSizeLimits limits;
+ limits.max_payload_len = 7;
+ limits.first_packet_reduction_len = 5;
+
+ std::vector<size_t> payload_sizes =
+ RtpPacketizer::SplitAboutEqually(28, limits);
+
+ EXPECT_LE(payload_sizes.front() + limits.first_packet_reduction_len,
+ limits.max_payload_len);
+}
+
+TEST(RtpPacketizerSplitAboutEqually,
SomePacketsAreSmallerRespectsLastPacketReductionLength) {
RtpPacketizer::PayloadSizeLimits limits;
limits.max_payload_len = 7;
@@ -139,7 +168,8 @@
limits.max_payload_len - limits.last_packet_reduction_len);
}
-TEST(RtpPacketizerVideoGeneric, SomePacketsAreSmallerPacketsAlmostEqualInSize) {
+TEST(RtpPacketizerSplitAboutEqually,
+ SomePacketsAreSmallerPacketsAlmostEqualInSize) {
RtpPacketizer::PayloadSizeLimits limits;
limits.max_payload_len = 7;
limits.last_packet_reduction_len = 5;
@@ -150,7 +180,7 @@
EXPECT_LE(EffectivePacketsSizeDifference(payload_sizes, limits), 1);
}
-TEST(RtpPacketizerVideoGeneric,
+TEST(RtpPacketizerSplitAboutEqually,
SomePacketsAreSmallerGeneratesMinimumNumberOfPackets) {
RtpPacketizer::PayloadSizeLimits limits;
limits.max_payload_len = 7;
@@ -164,5 +194,43 @@
EXPECT_THAT(payload_sizes, SizeIs(5));
}
+TEST(RtpPacketizerSplitAboutEqually, GivesNonZeroPayloadLengthEachPacket) {
+ RtpPacketizer::PayloadSizeLimits limits;
+ limits.max_payload_len = 600;
+ limits.first_packet_reduction_len = 500;
+ limits.last_packet_reduction_len = 550;
+
+ // Naive implementation would split 1450 payload + 1050 reduction bytes into 5
+ // packets 500 bytes each, thus leaving first packet zero bytes and even less
+ // to last packet.
+ std::vector<size_t> payload_sizes =
+ RtpPacketizer::SplitAboutEqually(1450, limits);
+
+ EXPECT_EQ(Sum(payload_sizes), 1450u);
+ EXPECT_THAT(payload_sizes, Each(Gt(0u)));
+}
+
+TEST(RtpPacketizerSplitAboutEqually,
+ OnePacketWhenExtraSpaceIsEnoughForSumOfFirstAndLastPacketReductions) {
+ RtpPacketizer::PayloadSizeLimits limits;
+ limits.max_payload_len = 30;
+ limits.first_packet_reduction_len = 6;
+ limits.last_packet_reduction_len = 4;
+
+ EXPECT_THAT(RtpPacketizer::SplitAboutEqually(20, limits), ElementsAre(20));
+}
+
+TEST(RtpPacketizerSplitAboutEqually,
+ TwoPacketsWhenExtraSpaceIsTooSmallForSumOfFirstAndLastPacketReductions) {
+ RtpPacketizer::PayloadSizeLimits limits;
+ limits.max_payload_len = 29;
+ limits.first_packet_reduction_len = 6;
+ limits.last_packet_reduction_len = 4;
+
+ // First packet needs two more extra bytes compared to last one,
+ // so should have two less payload bytes.
+ EXPECT_THAT(RtpPacketizer::SplitAboutEqually(20, limits), ElementsAre(9, 11));
+}
+
} // namespace
} // namespace webrtc
