diff options
Diffstat (limited to 'webrtc/modules/rtp_rtcp/source/forward_error_correction_internal.cc')
| -rw-r--r-- | webrtc/modules/rtp_rtcp/source/forward_error_correction_internal.cc | 106 |
1 files changed, 63 insertions, 43 deletions
diff --git a/webrtc/modules/rtp_rtcp/source/forward_error_correction_internal.cc b/webrtc/modules/rtp_rtcp/source/forward_error_correction_internal.cc index 6d9be90de1..fae59078b1 100644 --- a/webrtc/modules/rtp_rtcp/source/forward_error_correction_internal.cc +++ b/webrtc/modules/rtp_rtcp/source/forward_error_correction_internal.cc @@ -17,6 +17,8 @@ #include "webrtc/modules/rtp_rtcp/source/fec_private_tables_random.h" namespace { +using webrtc::fec_private_tables::kPacketMaskBurstyTbl; +using webrtc::fec_private_tables::kPacketMaskRandomTbl; // Allow for different modes of protection for packets in UEP case. enum ProtectionMode { @@ -37,8 +39,11 @@ enum ProtectionMode { // [0, num_rows * num_sub_mask_bytes] // \param[out] packet_mask A pointer to hold the output mask, of size // [0, x * num_mask_bytes], where x >= num_rows. -void FitSubMask(int num_mask_bytes, int num_sub_mask_bytes, int num_rows, - const uint8_t* sub_mask, uint8_t* packet_mask) { +void FitSubMask(int num_mask_bytes, + int num_sub_mask_bytes, + int num_rows, + const uint8_t* sub_mask, + uint8_t* packet_mask) { if (num_mask_bytes == num_sub_mask_bytes) { memcpy(packet_mask, sub_mask, num_rows * num_sub_mask_bytes); } else { @@ -70,13 +75,15 @@ void FitSubMask(int num_mask_bytes, int num_sub_mask_bytes, int num_rows, // \param[out] packet_mask A pointer to hold the output mask, of size // [0, x * num_mask_bytes], // where x >= end_row_fec. -// TODO (marpan): This function is doing three things at the same time: +// TODO(marpan): This function is doing three things at the same time: // shift within a byte, byte shift and resizing. // Split up into subroutines. -void ShiftFitSubMask(int num_mask_bytes, int res_mask_bytes, - int num_column_shift, int end_row, const uint8_t* sub_mask, +void ShiftFitSubMask(int num_mask_bytes, + int res_mask_bytes, + int num_column_shift, + int end_row, + const uint8_t* sub_mask, uint8_t* packet_mask) { - // Number of bit shifts within a byte const int num_bit_shifts = (num_column_shift % 8); const int num_byte_shifts = num_column_shift >> 3; @@ -128,7 +135,6 @@ void ShiftFitSubMask(int num_mask_bytes, int res_mask_bytes, // For the first byte in the row (j=0 case). shift_right_curr_byte = sub_mask[pkt_mask_idx2] >> num_bit_shifts; packet_mask[pkt_mask_idx] = shift_right_curr_byte; - } } } // namespace @@ -151,7 +157,9 @@ FecMaskType PacketMaskTable::InitMaskType(FecMaskType fec_mask_type, assert(num_media_packets <= static_cast<int>(sizeof(kPacketMaskRandomTbl) / sizeof(*kPacketMaskRandomTbl))); switch (fec_mask_type) { - case kFecMaskRandom: { return kFecMaskRandom; } + case kFecMaskRandom: { + return kFecMaskRandom; + } case kFecMaskBursty: { int max_media_packets = static_cast<int>(sizeof(kPacketMaskBurstyTbl) / sizeof(*kPacketMaskBurstyTbl)); @@ -170,17 +178,24 @@ FecMaskType PacketMaskTable::InitMaskType(FecMaskType fec_mask_type, // |fec_mask_type|. const uint8_t*** PacketMaskTable::InitMaskTable(FecMaskType fec_mask_type) { switch (fec_mask_type) { - case kFecMaskRandom: { return kPacketMaskRandomTbl; } - case kFecMaskBursty: { return kPacketMaskBurstyTbl; } + case kFecMaskRandom: { + return kPacketMaskRandomTbl; + } + case kFecMaskBursty: { + return kPacketMaskBurstyTbl; + } } assert(false); return kPacketMaskRandomTbl; } // Remaining protection after important (first partition) packet protection -void RemainingPacketProtection(int num_media_packets, int num_fec_remaining, - int num_fec_for_imp_packets, int num_mask_bytes, - ProtectionMode mode, uint8_t* packet_mask, +void RemainingPacketProtection(int num_media_packets, + int num_fec_remaining, + int num_fec_for_imp_packets, + int num_mask_bytes, + ProtectionMode mode, + uint8_t* packet_mask, const PacketMaskTable& mask_table) { if (mode == kModeNoOverlap) { // sub_mask21 @@ -191,8 +206,10 @@ void RemainingPacketProtection(int num_media_packets, int num_fec_remaining, const int res_mask_bytes = (l_bit == 1) ? kMaskSizeLBitSet : kMaskSizeLBitClear; - const uint8_t* packet_mask_sub_21 = mask_table.fec_packet_mask_table()[ - num_media_packets - num_fec_for_imp_packets - 1][num_fec_remaining - 1]; + const uint8_t* packet_mask_sub_21 = + mask_table.fec_packet_mask_table()[num_media_packets - + num_fec_for_imp_packets - + 1][num_fec_remaining - 1]; ShiftFitSubMask(num_mask_bytes, res_mask_bytes, num_fec_for_imp_packets, (num_fec_for_imp_packets + num_fec_remaining), @@ -201,8 +218,9 @@ void RemainingPacketProtection(int num_media_packets, int num_fec_remaining, } else if (mode == kModeOverlap || mode == kModeBiasFirstPacket) { // sub_mask22 - const uint8_t* packet_mask_sub_22 = mask_table - .fec_packet_mask_table()[num_media_packets - 1][num_fec_remaining - 1]; + const uint8_t* packet_mask_sub_22 = + mask_table.fec_packet_mask_table()[num_media_packets - + 1][num_fec_remaining - 1]; FitSubMask(num_mask_bytes, num_mask_bytes, num_fec_remaining, packet_mask_sub_22, @@ -217,41 +235,42 @@ void RemainingPacketProtection(int num_media_packets, int num_fec_remaining, } else { assert(false); } - } // Protection for important (first partition) packets -void ImportantPacketProtection(int num_fec_for_imp_packets, int num_imp_packets, - int num_mask_bytes, uint8_t* packet_mask, +void ImportantPacketProtection(int num_fec_for_imp_packets, + int num_imp_packets, + int num_mask_bytes, + uint8_t* packet_mask, const PacketMaskTable& mask_table) { const int l_bit = num_imp_packets > 16 ? 1 : 0; const int num_imp_mask_bytes = (l_bit == 1) ? kMaskSizeLBitSet : kMaskSizeLBitClear; // Get sub_mask1 from table - const uint8_t* packet_mask_sub_1 = mask_table.fec_packet_mask_table()[ - num_imp_packets - 1][num_fec_for_imp_packets - 1]; + const uint8_t* packet_mask_sub_1 = + mask_table.fec_packet_mask_table()[num_imp_packets - + 1][num_fec_for_imp_packets - 1]; FitSubMask(num_mask_bytes, num_imp_mask_bytes, num_fec_for_imp_packets, packet_mask_sub_1, packet_mask); - } // This function sets the protection allocation: i.e., how many FEC packets // to use for num_imp (1st partition) packets, given the: number of media // packets, number of FEC packets, and number of 1st partition packets. -int SetProtectionAllocation(int num_media_packets, int num_fec_packets, +int SetProtectionAllocation(int num_media_packets, + int num_fec_packets, int num_imp_packets) { - - // TODO (marpan): test different cases for protection allocation: + // TODO(marpan): test different cases for protection allocation: // Use at most (alloc_par * num_fec_packets) for important packets. float alloc_par = 0.5; int max_num_fec_for_imp = alloc_par * num_fec_packets; - int num_fec_for_imp_packets = - (num_imp_packets < max_num_fec_for_imp) ? num_imp_packets - : max_num_fec_for_imp; + int num_fec_for_imp_packets = (num_imp_packets < max_num_fec_for_imp) + ? num_imp_packets + : max_num_fec_for_imp; // Fall back to equal protection in this case if (num_fec_packets == 1 && (num_media_packets > 2 * num_imp_packets)) { @@ -268,7 +287,7 @@ int SetProtectionAllocation(int num_media_packets, int num_fec_packets, // Current version has 3 modes (options) to build UEP mask from existing ones. // Various other combinations may be added in future versions. // Longer-term, we may add another set of tables specifically for UEP cases. -// TODO (marpan): also consider modification of masks for bursty loss cases. +// TODO(marpan): also consider modification of masks for bursty loss cases. // Mask is characterized as (#packets_to_protect, #fec_for_protection). // Protection factor defined as: (#fec_for_protection / #packets_to_protect). @@ -306,13 +325,14 @@ int SetProtectionAllocation(int num_media_packets, int num_fec_packets, // Protection Mode 2 may be extended for a sort of sliding protection // (i.e., vary the number/density of "1s" across columns) across packets. -void UnequalProtectionMask(int num_media_packets, int num_fec_packets, - int num_imp_packets, int num_mask_bytes, +void UnequalProtectionMask(int num_media_packets, + int num_fec_packets, + int num_imp_packets, + int num_mask_bytes, uint8_t* packet_mask, const PacketMaskTable& mask_table) { - // Set Protection type and allocation - // TODO (marpan): test/update for best mode and some combinations thereof. + // TODO(marpan): test/update for best mode and some combinations thereof. ProtectionMode mode = kModeOverlap; int num_fec_for_imp_packets = 0; @@ -341,11 +361,12 @@ void UnequalProtectionMask(int num_media_packets, int num_fec_packets, num_fec_for_imp_packets, num_mask_bytes, mode, packet_mask, mask_table); } - } -void GeneratePacketMasks(int num_media_packets, int num_fec_packets, - int num_imp_packets, bool use_unequal_protection, +void GeneratePacketMasks(int num_media_packets, + int num_fec_packets, + int num_imp_packets, + bool use_unequal_protection, const PacketMaskTable& mask_table, uint8_t* packet_mask) { assert(num_media_packets > 0); @@ -361,16 +382,15 @@ void GeneratePacketMasks(int num_media_packets, int num_fec_packets, // Retrieve corresponding mask table directly:for equal-protection case. // Mask = (k,n-k), with protection factor = (n-k)/k, // where k = num_media_packets, n=total#packets, (n-k)=num_fec_packets. - memcpy(packet_mask, mask_table.fec_packet_mask_table()[ - num_media_packets - 1][num_fec_packets - 1], + memcpy(packet_mask, + mask_table.fec_packet_mask_table()[num_media_packets - + 1][num_fec_packets - 1], num_fec_packets * num_mask_bytes); - } else //UEP case - { + } else { // UEP case UnequalProtectionMask(num_media_packets, num_fec_packets, num_imp_packets, num_mask_bytes, packet_mask, mask_table); - } // End of UEP modification -} //End of GetPacketMasks +} // End of GetPacketMasks } // namespace internal } // namespace webrtc |