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304 lines
10 KiB
C++
304 lines
10 KiB
C++
#include "CodecSelectHelper.h"
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#include "platform/PlatformInterface.h"
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#include "media/base/media_constants.h"
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#include "media/base/codec.h"
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#include "absl/strings/match.h"
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#include "rtc_base/logging.h"
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#include "system_wrappers/include/field_trial.h"
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namespace tgcalls {
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namespace {
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using VideoFormat = webrtc::SdpVideoFormat;
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bool CompareFormats(const VideoFormat &a, const VideoFormat &b) {
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if (a.name < b.name) {
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return true;
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} else if (b.name < a.name) {
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return false;
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} else {
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return a.parameters < b.parameters;
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}
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}
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int FormatPriority(const VideoFormat &format, const std::vector<std::string> &preferredCodecs, std::shared_ptr<PlatformContext> platformContext) {
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static const auto kCodecs = {
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std::string(cricket::kAv1CodecName),
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std::string(cricket::kVp9CodecName),
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#ifndef WEBRTC_DISABLE_H265
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std::string(cricket::kH265CodecName),
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#endif
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std::string(cricket::kH264CodecName),
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std::string(cricket::kVp8CodecName),
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};
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static const auto kSupported = [platformContext] {
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const auto platform = PlatformInterface::SharedInstance();
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auto result = std::vector<std::string>();
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result.reserve(kCodecs.size());
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for (const auto &codec : kCodecs) {
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if (platform->supportsEncoding(codec, platformContext)) {
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result.push_back(codec);
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}
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}
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return result;
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}();
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for (int i = 0; i < preferredCodecs.size(); i++) {
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for (const auto &name : kSupported) {
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if (absl::EqualsIgnoreCase(format.name, preferredCodecs[i]) && absl::EqualsIgnoreCase(format.name, name)) {
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return i;
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}
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}
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}
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auto result = (int)preferredCodecs.size();
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for (const auto &name : kSupported) {
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if (absl::EqualsIgnoreCase(format.name, name)) {
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return result;
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}
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++result;
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}
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return -1;
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}
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bool ComparePriorities(const VideoFormat &a, const VideoFormat &b, const std::vector<std::string> &preferredCodecs, std::shared_ptr<PlatformContext> platformContext) {
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return FormatPriority(a, preferredCodecs, platformContext) < FormatPriority(b, preferredCodecs, platformContext);
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}
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std::vector<VideoFormat> FilterAndSortEncoders(std::vector<VideoFormat> list, const std::vector<std::string> &preferredCodecs, std::shared_ptr<PlatformContext> platformContext) {
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const auto listBegin = begin(list);
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const auto listEnd = end(list);
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std::sort(listBegin, listEnd, [&preferredCodecs, platformContext](const VideoFormat &lhs, const VideoFormat &rhs) {
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return ComparePriorities(lhs, rhs, preferredCodecs, platformContext);
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});
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auto eraseFrom = listBegin;
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auto eraseTill = eraseFrom;
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while (eraseTill != listEnd && FormatPriority(*eraseTill, preferredCodecs, platformContext) == -1) {
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++eraseTill;
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}
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if (eraseTill != eraseFrom) {
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list.erase(eraseFrom, eraseTill);
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}
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return list;
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}
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std::vector<VideoFormat> AppendUnique(
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std::vector<VideoFormat> list,
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std::vector<VideoFormat> other) {
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if (list.empty()) {
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return other;
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}
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list.reserve(list.size() + other.size());
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const auto oldBegin = &list[0];
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const auto oldEnd = oldBegin + list.size();
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for (auto &format : other) {
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if (std::find(oldBegin, oldEnd, format) == oldEnd) {
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list.push_back(std::move(format));
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}
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}
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return list;
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}
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std::vector<VideoFormat>::const_iterator FindEqualFormat(
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const std::vector<VideoFormat> &list,
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const VideoFormat &format) {
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return std::find_if(list.begin(), list.end(), [&](const VideoFormat &other) {
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return format.IsSameCodec(other);
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});
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}
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void AddDefaultFeedbackParams(cricket::VideoCodec *codec) {
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// Don't add any feedback params for RED and ULPFEC.
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if (codec->name == cricket::kRedCodecName || codec->name == cricket::kUlpfecCodecName)
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return;
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codec->AddFeedbackParam(cricket::FeedbackParam(cricket::kRtcpFbParamRemb, cricket::kParamValueEmpty));
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codec->AddFeedbackParam(
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cricket::FeedbackParam(cricket::kRtcpFbParamTransportCc, cricket::kParamValueEmpty));
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// Don't add any more feedback params for FLEXFEC.
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if (codec->name == cricket::kFlexfecCodecName)
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return;
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codec->AddFeedbackParam(cricket::FeedbackParam(cricket::kRtcpFbParamCcm, cricket::kRtcpFbCcmParamFir));
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codec->AddFeedbackParam(cricket::FeedbackParam(cricket::kRtcpFbParamNack, cricket::kParamValueEmpty));
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codec->AddFeedbackParam(cricket::FeedbackParam(cricket::kRtcpFbParamNack, cricket::kRtcpFbNackParamPli));
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if (codec->name == cricket::kVp8CodecName &&
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webrtc::field_trial::IsEnabled("WebRTC-RtcpLossNotification")) {
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codec->AddFeedbackParam(cricket::FeedbackParam(cricket::kRtcpFbParamLntf, cricket::kParamValueEmpty));
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}
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}
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std::vector<VideoFormat> RemoveScalabilityModes(
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std::vector<VideoFormat> list) {
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auto changed = false;
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for (auto &entry : list) {
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if (!entry.scalability_modes.empty()) {
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entry.scalability_modes = {};
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changed = true;
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}
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}
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if (changed && list.size() > 1) {
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for (auto i = list.end() - 1; i != list.begin(); --i) {
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if (std::find(list.begin(), i, *i) != i) {
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i = list.erase(i);
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}
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}
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}
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return list;
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}
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} // namespace
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VideoFormatsMessage ComposeSupportedFormats(
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std::vector<VideoFormat> encoders,
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std::vector<VideoFormat> decoders,
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const std::vector<std::string> &preferredCodecs,
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std::shared_ptr<PlatformContext> platformContext) {
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// We don't pass scalability_modes through signaling,
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// So we have to remove them here, otherwise lists are different.
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encoders = RemoveScalabilityModes(std::move(encoders));
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decoders = RemoveScalabilityModes(std::move(decoders));
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encoders = FilterAndSortEncoders(std::move(encoders), preferredCodecs, platformContext);
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auto result = VideoFormatsMessage();
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result.encodersCount = (int)encoders.size();
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result.formats = AppendUnique(std::move(encoders), std::move(decoders));
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for (const auto &format : result.formats) {
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RTC_LOG(LS_INFO) << "Format: " << format.ToString();
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}
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RTC_LOG(LS_INFO) << "First " << result.encodersCount << " formats are supported encoders.";
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return result;
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}
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CommonFormats ComputeCommonFormats(
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const VideoFormatsMessage &my,
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VideoFormatsMessage their) {
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assert(my.encodersCount <= my.formats.size());
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assert(their.encodersCount <= their.formats.size());
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for (const auto &format : their.formats) {
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RTC_LOG(LS_INFO) << "Their format: " << format.ToString();
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}
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RTC_LOG(LS_INFO) << "Their first " << their.encodersCount << " formats are supported encoders.";
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const auto myEncodersBegin = begin(my.formats);
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const auto myEncodersEnd = myEncodersBegin + my.encodersCount;
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const auto theirEncodersBegin = begin(their.formats);
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const auto theirEncodersEnd = theirEncodersBegin + their.encodersCount;
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auto result = CommonFormats();
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const auto addUnique = [&](const VideoFormat &format) {
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const auto already = std::find(
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result.list.begin(),
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result.list.end(),
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format);
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if (already == result.list.end()) {
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result.list.push_back(format);
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}
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};
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const auto addCommonAndFindFirst = [&](
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std::vector<VideoFormat>::const_iterator begin,
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std::vector<VideoFormat>::const_iterator end,
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const std::vector<VideoFormat> &decoders) {
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auto first = VideoFormat(std::string());
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for (auto i = begin; i != end; ++i) {
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const auto &format = *i;
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const auto j = FindEqualFormat(decoders, format);
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if (j != decoders.end()) {
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if (first.name.empty()) {
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first = format;
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}
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addUnique(format);
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addUnique(*j);
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};
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}
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return first;
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};
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result.list.reserve(my.formats.size() + their.formats.size());
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auto myEncoderFormat = addCommonAndFindFirst(
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myEncodersBegin,
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myEncodersEnd,
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their.formats);
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auto theirEncoderFormat = addCommonAndFindFirst(
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theirEncodersBegin,
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theirEncodersEnd,
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my.formats);
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std::sort(begin(result.list), end(result.list), CompareFormats);
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if (!myEncoderFormat.name.empty()) {
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const auto i = std::find(begin(result.list), end(result.list), myEncoderFormat);
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assert(i != end(result.list));
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result.myEncoderIndex = (i - begin(result.list));
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}
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for (const auto &format : result.list) {
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RTC_LOG(LS_INFO) << "Common format: " << format.ToString();
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}
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RTC_LOG(LS_INFO) << "My encoder: " << (result.myEncoderIndex >= 0 ? result.list[result.myEncoderIndex].ToString() : "(null)");
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RTC_LOG(LS_INFO) << "Their encoder: " << (!theirEncoderFormat.name.empty() ? theirEncoderFormat.ToString() : "(null)");
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return result;
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}
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CommonCodecs AssignPayloadTypesAndDefaultCodecs(CommonFormats &&formats) {
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if (formats.list.empty()) {
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return CommonCodecs();
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}
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constexpr int kFirstDynamicPayloadType = 96;
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constexpr int kLastDynamicPayloadType = 127;
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int payload_type = kFirstDynamicPayloadType;
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formats.list.push_back(webrtc::SdpVideoFormat(cricket::kRedCodecName));
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formats.list.push_back(webrtc::SdpVideoFormat(cricket::kUlpfecCodecName));
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if (true) {
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webrtc::SdpVideoFormat flexfec_format(cricket::kFlexfecCodecName);
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// This value is currently arbitrarily set to 10 seconds. (The unit
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// is microseconds.) This parameter MUST be present in the SDP, but
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// we never use the actual value anywhere in our code however.
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// TODO(brandtr): Consider honouring this value in the sender and receiver.
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flexfec_format.parameters = { {cricket::kFlexfecFmtpRepairWindow, "10000000"} };
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formats.list.push_back(flexfec_format);
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}
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auto inputIndex = 0;
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auto result = CommonCodecs();
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result.list.reserve(2 * formats.list.size() - 2);
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for (const auto &format : formats.list) {
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cricket::VideoCodec codec(format);
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codec.id = payload_type;
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AddDefaultFeedbackParams(&codec);
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if (inputIndex++ == formats.myEncoderIndex) {
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result.myEncoderIndex = result.list.size();
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}
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result.list.push_back(codec);
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// Increment payload type.
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++payload_type;
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if (payload_type > kLastDynamicPayloadType) {
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RTC_LOG(LS_ERROR) << "Out of dynamic payload types, skipping the rest.";
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break;
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}
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// Add associated RTX codec for non-FEC codecs.
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if (!absl::EqualsIgnoreCase(codec.name, cricket::kUlpfecCodecName) &&
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!absl::EqualsIgnoreCase(codec.name, cricket::kFlexfecCodecName)) {
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result.list.push_back(cricket::VideoCodec::CreateRtxCodec(payload_type, codec.id));
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// Increment payload type.
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++payload_type;
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if (payload_type > kLastDynamicPayloadType) {
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RTC_LOG(LS_ERROR) << "Out of dynamic payload types, skipping the rest.";
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break;
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}
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}
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}
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return result;
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}
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} // namespace tgcalls
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