diff --git a/webrtc/modules/rtp_rtcp/source/rtcp_sender.cc b/webrtc/modules/rtp_rtcp/source/rtcp_sender.cc index 5ebd4a895d..e118fb262c 100644 --- a/webrtc/modules/rtp_rtcp/source/rtcp_sender.cc +++ b/webrtc/modules/rtp_rtcp/source/rtcp_sender.cc @@ -638,16 +638,48 @@ RTCPSender::BuildResult RTCPSender::BuildRPSI(RtcpContext* ctx) { } RTCPSender::BuildResult RTCPSender::BuildREMB(RtcpContext* ctx) { - rtcp::Remb remb; - remb.From(ssrc_); - for (uint32_t ssrc : remb_ssrcs_) - remb.AppliesTo(ssrc); - remb.WithBitrateBps(remb_bitrate_); - - PacketBuiltCallback callback(ctx); - if (!callback.BuildPacket(remb)) + // sanity + if (ctx->position + 20 + 4 * remb_ssrcs_.size() >= IP_PACKET_SIZE) return BuildResult::kTruncated; + // add application layer feedback + uint8_t FMT = 15; + *ctx->AllocateData(1) = 0x80 + FMT; + *ctx->AllocateData(1) = 206; + + *ctx->AllocateData(1) = 0; + *ctx->AllocateData(1) = static_cast(remb_ssrcs_.size() + 4); + + // Add our own SSRC + ByteWriter::WriteBigEndian(ctx->AllocateData(4), ssrc_); + + // Remote SSRC must be 0 + ByteWriter::WriteBigEndian(ctx->AllocateData(4), 0); + + *ctx->AllocateData(1) = 'R'; + *ctx->AllocateData(1) = 'E'; + *ctx->AllocateData(1) = 'M'; + *ctx->AllocateData(1) = 'B'; + + *ctx->AllocateData(1) = remb_ssrcs_.size(); + // 6 bit Exp + // 18 bit mantissa + uint8_t brExp = 0; + for (uint32_t i = 0; i < 64; i++) { + if (remb_bitrate_ <= (0x3FFFFu << i)) { + brExp = i; + break; + } + } + const uint32_t brMantissa = (remb_bitrate_ >> brExp); + *ctx->AllocateData(1) = + static_cast((brExp << 2) + ((brMantissa >> 16) & 0x03)); + *ctx->AllocateData(1) = static_cast(brMantissa >> 8); + *ctx->AllocateData(1) = static_cast(brMantissa); + + for (size_t i = 0; i < remb_ssrcs_.size(); i++) + ByteWriter::WriteBigEndian(ctx->AllocateData(4), remb_ssrcs_[i]); + TRACE_EVENT_INSTANT0(TRACE_DISABLED_BY_DEFAULT("webrtc_rtp"), "RTCPSender::REMB");