523589dbd8
Unfortunately, H264 makes it non-trivial to compare video formats for equality. For every video format besides H264 it's enough to look at the name, but for H264, we need to dig into the parameters. This logic is currently in several places, and this CL unifies it to one place. Bug: webrtc:7925 Change-Id: I83a516b108d6b4d6792fd0bf1d24296916d9f7fa Reviewed-on: https://webrtc-review.googlesource.com/25120 Commit-Queue: Magnus Jedvert <magjed@webrtc.org> Reviewed-by: Sami Kalliomäki <sakal@webrtc.org> Cr-Commit-Position: refs/heads/master@{#20853}
108 lines
4.1 KiB
C++
108 lines
4.1 KiB
C++
/*
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* Copyright (c) 2017 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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#ifndef MEDIA_BASE_H264_PROFILE_LEVEL_ID_H_
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#define MEDIA_BASE_H264_PROFILE_LEVEL_ID_H_
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#include <map>
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#include <string>
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#include "api/optional.h"
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#include "common_types.h" // NOLINT(build/include)
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namespace webrtc {
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namespace H264 {
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// Map containting SDP codec parameters.
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typedef std::map<std::string, std::string> CodecParameterMap;
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// All values are equal to ten times the level number, except level 1b which is
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// special.
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enum Level {
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kLevel1_b = 0,
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kLevel1 = 10,
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kLevel1_1 = 11,
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kLevel1_2 = 12,
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kLevel1_3 = 13,
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kLevel2 = 20,
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kLevel2_1 = 21,
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kLevel2_2 = 22,
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kLevel3 = 30,
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kLevel3_1 = 31,
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kLevel3_2 = 32,
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kLevel4 = 40,
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kLevel4_1 = 41,
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kLevel4_2 = 42,
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kLevel5 = 50,
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kLevel5_1 = 51,
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kLevel5_2 = 52
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};
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struct ProfileLevelId {
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ProfileLevelId(Profile profile, Level level)
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: profile(profile), level(level) {}
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Profile profile;
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Level level;
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};
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// Parse profile level id that is represented as a string of 3 hex bytes.
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// Nothing will be returned if the string is not a recognized H264
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// profile level id.
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rtc::Optional<ProfileLevelId> ParseProfileLevelId(const char* str);
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// Parse profile level id that is represented as a string of 3 hex bytes
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// contained in an SDP key-value map. A default profile level id will be
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// returned if the profile-level-id key is missing. Nothing will be returned if
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// the key is present but the string is invalid.
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rtc::Optional<ProfileLevelId> ParseSdpProfileLevelId(
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const CodecParameterMap& params);
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// Given that a decoder supports up to a given frame size (in pixels) at up to a
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// given number of frames per second, return the highest H.264 level where it
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// can guarantee that it will be able to support all valid encoded streams that
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// are within that level.
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rtc::Optional<Level> SupportedLevel(int max_frame_pixel_count, float max_fps);
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// Returns canonical string representation as three hex bytes of the profile
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// level id, or returns nothing for invalid profile level ids.
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rtc::Optional<std::string> ProfileLevelIdToString(
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const ProfileLevelId& profile_level_id);
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// Generate codec parameters that will be used as answer in an SDP negotiation
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// based on local supported parameters and remote offered parameters. Both
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// |local_supported_params|, |remote_offered_params|, and |answer_params|
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// represent sendrecv media descriptions, i.e they are a mix of both encode and
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// decode capabilities. In theory, when the profile in |local_supported_params|
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// represent a strict superset of the profile in |remote_offered_params|, we
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// could limit the profile in |answer_params| to the profile in
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// |remote_offered_params|. However, to simplify the code, each supported H264
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// profile should be listed explicitly in the list of local supported codecs,
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// even if they are redundant. Then each local codec in the list should be
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// tested one at a time against the remote codec, and only when the profiles are
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// equal should this function be called. Therefore, this function does not need
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// to handle profile intersection, and the profile of |local_supported_params|
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// and |remote_offered_params| must be equal before calling this function. The
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// parameters that are used when negotiating are the level part of
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// profile-level-id and level-asymmetry-allowed.
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void GenerateProfileLevelIdForAnswer(
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const CodecParameterMap& local_supported_params,
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const CodecParameterMap& remote_offered_params,
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CodecParameterMap* answer_params);
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// Returns true if the parameters have the same H264 profile, i.e. the same
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// H264::Profile (Baseline, High, etc).
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bool IsSameH264Profile(const CodecParameterMap& params1,
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const CodecParameterMap& params2);
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} // namespace H264
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} // namespace webrtc
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#endif // MEDIA_BASE_H264_PROFILE_LEVEL_ID_H_
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