sdp_video_format_utils.h

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/*

 *  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_VIDEO_FORMAT_UTILS_H_

#define MEDIA_BASE_SDP_VIDEO_FORMAT_UTILS_H_

#include "absl/types/optional.h"

#include "api/video_codecs/sdp_video_format.h"

namespace webrtc {

// Generate codec parameters that will be used as answer in an SDP negotiation

// based on local supported parameters and remote offered parameters. Both

// `local_supported_params`, `remote_offered_params`, and `answer_params`

// represent sendrecv media descriptions, i.e they are a mix of both encode and

// decode capabilities. In theory, when the profile in `local_supported_params`

// represent a strict superset of the profile in `remote_offered_params`, we

// could limit the profile in `answer_params` to the profile in

// `remote_offered_params`. However, to simplify the code, each supported H264

// profile should be listed explicitly in the list of local supported codecs,

// even if they are redundant. Then each local codec in the list should be

// tested one at a time against the remote codec, and only when the profiles are

// equal should this function be called. Therefore, this function does not need

// to handle profile intersection, and the profile of `local_supported_params`

// and `remote_offered_params` must be equal before calling this function. The

// parameters that are used when negotiating are the level part of

// profile-level-id and level-asymmetry-allowed.

void H264GenerateProfileLevelIdForAnswer(

    const CodecParameterMap& local_supported_params,

    const CodecParameterMap& remote_offered_params,

    CodecParameterMap* answer_params);

#ifdef RTC_ENABLE_H265

// Works similarly as H264GenerateProfileLevelIdForAnswer, but generates codec

// parameters that will be used as answer for H.265.

// Media configuration parameters, except level-id, must be used symmetrically.

// For level-id, the highest level indicated by the answer must not be higher

// than that indicated by the offer.

void H265GenerateProfileTierLevelForAnswer(

    const CodecParameterMap& local_supported_params,

    const CodecParameterMap& remote_offered_params,

    CodecParameterMap* answer_params);

#endif

// 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 CodecParameterMap& 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 CodecParameterMap& params);

// Determines whether the non-standard x-google-per-layer-pli fmtp is present

// in the parameters and has a value of "1".

bool SupportsPerLayerPictureLossIndication(const CodecParameterMap& params);

}  // namespace webrtc

#endif  // MEDIA_BASE_SDP_VIDEO_FORMAT_UTILS_H_