c3fcee7c3a
This is a refactor to simplify a follow-up CL of adding SdpVideoFormat::IsSameCodec. The original files media/base/h264_profile_level_id.* and media/base/vp9_profile.h must be kept until downstream projects stop using them. Bug: chroimium:1187565 Change-Id: Ib39eca095a3d61939a914d9bffaf4b891ddd222f Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/215236 Reviewed-by: Harald Alvestrand <hta@webrtc.org> Reviewed-by: Kári Helgason <kthelgason@webrtc.org> Reviewed-by: Niels Moller <nisse@webrtc.org> Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org> Commit-Queue: Johannes Kron <kron@webrtc.org> Cr-Commit-Position: refs/heads/master@{#33782}
122 lines
4.4 KiB
C++
122 lines
4.4 KiB
C++
/*
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* Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "media/base/sdp_video_format_utils.h"
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#include <cstring>
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#include <map>
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#include <utility>
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#include "api/video_codecs/h264_profile_level_id.h"
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#include "rtc_base/checks.h"
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#include "rtc_base/string_to_number.h"
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namespace webrtc {
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namespace {
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const char kProfileLevelId[] = "profile-level-id";
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const char kH264LevelAsymmetryAllowed[] = "level-asymmetry-allowed";
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// Max frame rate for VP8 and VP9 video.
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const char kVPxFmtpMaxFrameRate[] = "max-fr";
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// Max frame size for VP8 and VP9 video.
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const char kVPxFmtpMaxFrameSize[] = "max-fs";
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const int kVPxFmtpFrameSizeSubBlockPixels = 256;
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bool IsH264LevelAsymmetryAllowed(const SdpVideoFormat::Parameters& params) {
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const auto it = params.find(kH264LevelAsymmetryAllowed);
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return it != params.end() && strcmp(it->second.c_str(), "1") == 0;
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}
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// Compare H264 levels and handle the level 1b case.
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bool H264LevelIsLess(H264Level a, H264Level b) {
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if (a == H264Level::kLevel1_b)
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return b != H264Level::kLevel1 && b != H264Level::kLevel1_b;
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if (b == H264Level::kLevel1_b)
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return a == H264Level::kLevel1;
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return a < b;
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}
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H264Level H264LevelMin(H264Level a, H264Level b) {
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return H264LevelIsLess(a, b) ? a : b;
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}
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absl::optional<int> ParsePositiveNumberFromParams(
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const SdpVideoFormat::Parameters& params,
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const char* parameter_name) {
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const auto max_frame_rate_it = params.find(parameter_name);
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if (max_frame_rate_it == params.end())
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return absl::nullopt;
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const absl::optional<int> i =
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rtc::StringToNumber<int>(max_frame_rate_it->second);
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if (!i.has_value() || i.value() <= 0)
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return absl::nullopt;
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return i;
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}
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} // namespace
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// Set level according to https://tools.ietf.org/html/rfc6184#section-8.2.2.
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void H264GenerateProfileLevelIdForAnswer(
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const SdpVideoFormat::Parameters& local_supported_params,
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const SdpVideoFormat::Parameters& remote_offered_params,
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SdpVideoFormat::Parameters* answer_params) {
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// If both local and remote haven't set profile-level-id, they are both using
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// the default profile. In this case, don't set profile-level-id in answer
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// either.
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if (!local_supported_params.count(kProfileLevelId) &&
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!remote_offered_params.count(kProfileLevelId)) {
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return;
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}
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// Parse profile-level-ids.
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const absl::optional<H264ProfileLevelId> local_profile_level_id =
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ParseSdpForH264ProfileLevelId(local_supported_params);
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const absl::optional<H264ProfileLevelId> remote_profile_level_id =
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ParseSdpForH264ProfileLevelId(remote_offered_params);
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// The local and remote codec must have valid and equal H264 Profiles.
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RTC_DCHECK(local_profile_level_id);
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RTC_DCHECK(remote_profile_level_id);
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RTC_DCHECK_EQ(local_profile_level_id->profile,
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remote_profile_level_id->profile);
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// Parse level information.
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const bool level_asymmetry_allowed =
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IsH264LevelAsymmetryAllowed(local_supported_params) &&
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IsH264LevelAsymmetryAllowed(remote_offered_params);
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const H264Level local_level = local_profile_level_id->level;
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const H264Level remote_level = remote_profile_level_id->level;
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const H264Level min_level = H264LevelMin(local_level, remote_level);
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// Determine answer level. When level asymmetry is not allowed, level upgrade
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// is not allowed, i.e., the level in the answer must be equal to or lower
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// than the level in the offer.
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const H264Level answer_level =
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level_asymmetry_allowed ? local_level : min_level;
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// Set the resulting profile-level-id in the answer parameters.
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(*answer_params)[kProfileLevelId] = *H264ProfileLevelIdToString(
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H264ProfileLevelId(local_profile_level_id->profile, answer_level));
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}
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absl::optional<int> ParseSdpForVPxMaxFrameRate(
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const SdpVideoFormat::Parameters& params) {
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return ParsePositiveNumberFromParams(params, kVPxFmtpMaxFrameRate);
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}
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absl::optional<int> ParseSdpForVPxMaxFrameSize(
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const SdpVideoFormat::Parameters& params) {
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const absl::optional<int> i =
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ParsePositiveNumberFromParams(params, kVPxFmtpMaxFrameSize);
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return i ? absl::make_optional(i.value() * kVPxFmtpFrameSizeSubBlockPixels)
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: absl::nullopt;
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}
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} // namespace webrtc
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