Parse max-fr and max-fs from SDP FMTP line

max-fr and max-fs are mandatory fields for VP8 and VP9.

Add parsing as a first step to enable use of these fields.

Bug: chromium:1032518
Change-Id: I4fd8f7f84f6303d646fb3f5313a02d6cf4160346
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/162801
Commit-Queue: Johannes Kron <kron@webrtc.org>
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#30114}

media/BUILD.gn

@@ -63,6 +63,20 @@ rtc_library("rtc_vp9_profile") {
   ]
 }
 
+rtc_library("rtc_sdp_fmtp_utils") {
+  visibility = [ "*" ]
+  sources = [
+    "base/sdp_fmtp_utils.cc",
+    "base/sdp_fmtp_utils.h",
+  ]
+
+  deps = [
+    "../api/video_codecs:video_codecs_api",
+    "../rtc_base:stringutils",
+    "//third_party/abseil-cpp/absl/types:optional",
+  ]
+}
+
 rtc_library("rtc_media_base") {
   visibility = [ "*" ]
   defines = []
@@ -523,6 +537,7 @@ if (rtc_include_tests) {
       ":rtc_media_base",
       ":rtc_media_engine_defaults",
       ":rtc_media_tests_utils",
+      ":rtc_sdp_fmtp_utils",
       ":rtc_simulcast_encoder_adapter",
       ":rtc_vp9_profile",
       "../:webrtc_common",
@@ -589,6 +604,7 @@ if (rtc_include_tests) {
       "base/codec_unittest.cc",
       "base/rtp_data_engine_unittest.cc",
       "base/rtp_utils_unittest.cc",
+      "base/sdp_fmtp_utils_unittest.cc",
       "base/stream_params_unittest.cc",
       "base/turn_utils_unittest.cc",
       "base/video_adapter_unittest.cc",

media/base/sdp_fmtp_utils.cc

@@ -0,0 +1,55 @@
+/*
+ *  Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "media/base/sdp_fmtp_utils.h"
+
+#include <map>
+#include <utility>
+
+#include "rtc_base/string_to_number.h"
+
+namespace webrtc {
+namespace {
+// Max frame rate for VP8 and VP9 video.
+const char kVPxFmtpMaxFrameRate[] = "max-fr";
+// Max frame size for VP8 and VP9 video.
+const char kVPxFmtpMaxFrameSize[] = "max-fs";
+const int kVPxFmtpFrameSizeSubBlockPixels = 256;
+
+absl::optional<int> ParsePositiveNumberFromParams(
+    const SdpVideoFormat::Parameters& params,
+    const char* parameter_name) {
+  const auto max_frame_rate_it = params.find(parameter_name);
+  if (max_frame_rate_it == params.end())
+    return absl::nullopt;
+
+  const absl::optional<int> i =
+      rtc::StringToNumber<int>(max_frame_rate_it->second);
+  if (!i.has_value() || i.value() <= 0)
+    return absl::nullopt;
+  return i;
+}
+
+}  // namespace
+
+absl::optional<int> ParseSdpForVPxMaxFrameRate(
+    const SdpVideoFormat::Parameters& params) {
+  return ParsePositiveNumberFromParams(params, kVPxFmtpMaxFrameRate);
+}
+
+absl::optional<int> ParseSdpForVPxMaxFrameSize(
+    const SdpVideoFormat::Parameters& params) {
+  const absl::optional<int> i =
+      ParsePositiveNumberFromParams(params, kVPxFmtpMaxFrameSize);
+  return i ? absl::make_optional(i.value() * kVPxFmtpFrameSizeSubBlockPixels)
+           : absl::nullopt;
+}
+
+}  // namespace webrtc

media/base/sdp_fmtp_utils.h

@@ -0,0 +1,32 @@
+/*
+ *  Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef MEDIA_BASE_SDP_FMTP_UTILS_H_
+#define MEDIA_BASE_SDP_FMTP_UTILS_H_
+
+#include "absl/types/optional.h"
+#include "api/video_codecs/sdp_video_format.h"
+
+namespace webrtc {
+
+// Parse max frame rate from SDP FMTP line. absl::nullopt is returned if the
+// field is missing or not a number.
+absl::optional<int> ParseSdpForVPxMaxFrameRate(
+    const SdpVideoFormat::Parameters& params);
+
+// Parse max frame size from SDP FMTP line. absl::nullopt is returned if the
+// field is missing or not a number. Please note that the value is stored in sub
+// blocks but the returned value is in total number of pixels.
+absl::optional<int> ParseSdpForVPxMaxFrameSize(
+    const SdpVideoFormat::Parameters& params);
+
+}  // namespace webrtc
+
+#endif  // MEDIA_BASE_SDP_FMTP_UTILS_H__

media/base/sdp_fmtp_utils_unittest.cc

@@ -0,0 +1,68 @@
+/*
+ *  Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "media/base/sdp_fmtp_utils.h"
+
+#include <string.h>
+#include <map>
+#include <utility>
+
+#include "rtc_base/string_to_number.h"
+#include "test/gtest.h"
+
+namespace webrtc {
+namespace {
+// Max frame rate for VP8 and VP9 video.
+const char kVPxFmtpMaxFrameRate[] = "max-fr";
+// Max frame size for VP8 and VP9 video.
+const char kVPxFmtpMaxFrameSize[] = "max-fs";
+}  // namespace
+
+TEST(SdpFmtpUtilsTest, MaxFrameRateIsMissingOrInvalid) {
+  SdpVideoFormat::Parameters params;
+  absl::optional<int> empty = ParseSdpForVPxMaxFrameRate(params);
+  EXPECT_FALSE(empty);
+  params[kVPxFmtpMaxFrameRate] = "-1";
+  EXPECT_FALSE(ParseSdpForVPxMaxFrameRate(params));
+  params[kVPxFmtpMaxFrameRate] = "0";
+  EXPECT_FALSE(ParseSdpForVPxMaxFrameRate(params));
+  params[kVPxFmtpMaxFrameRate] = "abcde";
+  EXPECT_FALSE(ParseSdpForVPxMaxFrameRate(params));
+}
+
+TEST(SdpFmtpUtilsTest, MaxFrameRateIsSpecified) {
+  SdpVideoFormat::Parameters params;
+  params[kVPxFmtpMaxFrameRate] = "30";
+  EXPECT_EQ(ParseSdpForVPxMaxFrameRate(params), 30);
+  params[kVPxFmtpMaxFrameRate] = "60";
+  EXPECT_EQ(ParseSdpForVPxMaxFrameRate(params), 60);
+}
+
+TEST(SdpFmtpUtilsTest, MaxFrameSizeIsMissingOrInvalid) {
+  SdpVideoFormat::Parameters params;
+  absl::optional<int> empty = ParseSdpForVPxMaxFrameSize(params);
+  EXPECT_FALSE(empty);
+  params[kVPxFmtpMaxFrameSize] = "-1";
+  EXPECT_FALSE(ParseSdpForVPxMaxFrameSize(params));
+  params[kVPxFmtpMaxFrameSize] = "0";
+  EXPECT_FALSE(ParseSdpForVPxMaxFrameSize(params));
+  params[kVPxFmtpMaxFrameSize] = "abcde";
+  EXPECT_FALSE(ParseSdpForVPxMaxFrameSize(params));
+}
+
+TEST(SdpFmtpUtilsTest, MaxFrameSizeIsSpecified) {
+  SdpVideoFormat::Parameters params;
+  params[kVPxFmtpMaxFrameSize] = "8100";  // 1920 x 1080 / (16^2)
+  EXPECT_EQ(ParseSdpForVPxMaxFrameSize(params), 1920 * 1080);
+  params[kVPxFmtpMaxFrameSize] = "32400";  // 3840 x 2160 / (16^2)
+  EXPECT_EQ(ParseSdpForVPxMaxFrameSize(params), 3840 * 2160);
+}
+
+}  // namespace webrtc