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Move InsertZeroColumns and CopyColumn to ::internal.

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These functions operate directly on the packet masks, and are thus not directly
involved in the FEC encoding/decoding operation. The ::internal namespace is used
for packet mask-related functions, and will be renamed later on.

This CL should have no impact on functionality or performance.

BUG=webrtc:5654

Review-Url: https://codereview.webrtc.org/2269893002
Cr-Commit-Position: refs/heads/master@{#13914}
This commit is contained in:
brandtr 2016-08-25 02:36:01 -07:00 committed by Commit bot
parent 7a770e0a61
commit 00e45bb09d
4 changed files with 74 additions and 63 deletions
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56
webrtc/modules/rtp_rtcp/source/forward_error_correction.cc
View File

@ -306,10 +306,10 @@ int ForwardErrorCorrection::InsertZerosInBitMasks(
++media_packets_it;
// Insert the first column.
CopyColumn(tmp_packet_mask_, new_mask_bytes, packet_mask, num_mask_bytes,
num_fec_packets, 0, 0);
int new_bit_index = 1;
int old_bit_index = 1;
internal::CopyColumn(tmp_packet_mask_, new_mask_bytes, packet_mask_,
num_mask_bytes, num_fec_packets, 0, 0);
size_t new_bit_index = 1;
size_t old_bit_index = 1;
// Insert zeros in the bit mask for every hole in the sequence.
while (media_packets_it != media_packets.end()) {
if (new_bit_index == 8 * kMaskSizeLBitSet) {
@ -317,15 +317,17 @@ int ForwardErrorCorrection::InsertZerosInBitMasks(
break;
}
uint16_t seq_num = ParseSequenceNumber((*media_packets_it)->data);
const int zeros_to_insert =
const int num_zeros_to_insert =
static_cast<uint16_t>(seq_num - prev_seq_num - 1);
if (zeros_to_insert > 0) {
InsertZeroColumns(zeros_to_insert, tmp_packet_mask_, new_mask_bytes,
num_fec_packets, new_bit_index);
if (num_zeros_to_insert > 0) {
internal::InsertZeroColumns(num_zeros_to_insert, tmp_packet_mask_,
new_mask_bytes, num_fec_packets,
new_bit_index);
}
new_bit_index += zeros_to_insert;
CopyColumn(tmp_packet_mask_, new_mask_bytes, packet_mask, num_mask_bytes,
num_fec_packets, new_bit_index, old_bit_index);
new_bit_index += num_zeros_to_insert;
internal::CopyColumn(tmp_packet_mask_, new_mask_bytes, packet_mask_,
num_mask_bytes, num_fec_packets, new_bit_index,
old_bit_index);
++new_bit_index;
++old_bit_index;
prev_seq_num = seq_num;
@ -343,38 +345,6 @@ int ForwardErrorCorrection::InsertZerosInBitMasks(
return new_bit_index;
}
void ForwardErrorCorrection::InsertZeroColumns(int num_zeros,
uint8_t* new_mask,
int new_mask_bytes,
int num_fec_packets,
int new_bit_index) {
for (uint16_t row = 0; row < num_fec_packets; ++row) {
const int new_byte_index = row * new_mask_bytes + new_bit_index / 8;
const int max_shifts = (7 - (new_bit_index % 8));
new_mask[new_byte_index] <<= std::min(num_zeros, max_shifts);
}
}
void ForwardErrorCorrection::CopyColumn(uint8_t* new_mask,
int new_mask_bytes,
uint8_t* old_mask,
int old_mask_bytes,
int num_fec_packets,
int new_bit_index,
int old_bit_index) {
// Copy column from the old mask to the beginning of the new mask and shift it
// out from the old mask.
for (uint16_t row = 0; row < num_fec_packets; ++row) {
int new_byte_index = row * new_mask_bytes + new_bit_index / 8;
int old_byte_index = row * old_mask_bytes + old_bit_index / 8;
new_mask[new_byte_index] |= ((old_mask[old_byte_index] & 0x80) >> 7);
if (new_bit_index % 8 != 7) {
new_mask[new_byte_index] <<= 1;
}
old_mask[old_byte_index] <<= 1;
}
}
void ForwardErrorCorrection::GenerateFecUlpHeaders(
const PacketList& media_packets,
uint8_t* packet_mask,

20
webrtc/modules/rtp_rtcp/source/forward_error_correction.h
View File

@ -229,26 +229,6 @@ class ForwardErrorCorrection {
uint8_t* packet_mask, int num_mask_bytes,
int num_fec_packets);
// Inserts |num_zeros| zero columns into |new_mask| at position
// |new_bit_index|. If the current byte of |new_mask| can't fit all zeros, the
// byte will be filled with zeros from |new_bit_index|, but the next byte will
// be untouched.
static void InsertZeroColumns(int num_zeros, uint8_t* new_mask,
int new_mask_bytes, int num_fec_packets,
int new_bit_index);
// Copies the left most bit column from the byte pointed to by
// |old_bit_index| in |old_mask| to the right most column of the byte pointed
// to by |new_bit_index| in |new_mask|. |old_mask_bytes| and |new_mask_bytes|
// represent the number of bytes used per row for each mask. |num_fec_packets|
// represent the number of rows of the masks.
// The copied bit is shifted out from |old_mask| and is shifted one step to
// the left in |new_mask|. |new_mask| will contain "xxxx xxn0" after this
// operation, where x are previously inserted bits and n is the new bit.
static void CopyColumn(uint8_t* new_mask, int new_mask_bytes,
uint8_t* old_mask, int old_mask_bytes,
int num_fec_packets, int new_bit_index,
int old_bit_index);
void GenerateFecUlpHeaders(const PacketList& media_packets,
uint8_t* packet_mask, int num_fec_packets,

34
webrtc/modules/rtp_rtcp/source/forward_error_correction_internal.cc
View File

@ -13,6 +13,8 @@
#include <assert.h>
#include <string.h>
#include <algorithm>
#include "webrtc/modules/rtp_rtcp/source/fec_private_tables_bursty.h"
#include "webrtc/modules/rtp_rtcp/source/fec_private_tables_random.h"
@ -392,5 +394,37 @@ void GeneratePacketMasks(int num_media_packets,
} // End of UEP modification
} // End of GetPacketMasks
void InsertZeroColumns(int num_zeros,
uint8_t* new_mask,
int new_mask_bytes,
int num_fec_packets,
int new_bit_index) {
for (uint16_t row = 0; row < num_fec_packets; ++row) {
const int new_byte_index = row * new_mask_bytes + new_bit_index / 8;
const int max_shifts = (7 - (new_bit_index % 8));
new_mask[new_byte_index] <<= std::min(num_zeros, max_shifts);
}
}
void CopyColumn(uint8_t* new_mask,
int new_mask_bytes,
uint8_t* old_mask,
int old_mask_bytes,
int num_fec_packets,
int new_bit_index,
int old_bit_index) {
// Copy column from the old mask to the beginning of the new mask and shift it
// out from the old mask.
for (uint16_t row = 0; row < num_fec_packets; ++row) {
int new_byte_index = row * new_mask_bytes + new_bit_index / 8;
int old_byte_index = row * old_mask_bytes + old_bit_index / 8;
new_mask[new_byte_index] |= ((old_mask[old_byte_index] & 0x80) >> 7);
if (new_bit_index % 8 != 7) {
new_mask[new_byte_index] <<= 1;
}
old_mask[old_byte_index] <<= 1;
}
}
} // namespace internal
} // namespace webrtc

27
webrtc/modules/rtp_rtcp/source/forward_error_correction_internal.h
View File

@ -65,6 +65,33 @@ void GeneratePacketMasks(int num_media_packets, int num_fec_packets,
const PacketMaskTable& mask_table,
uint8_t* packet_mask);
// Inserts |num_zeros| zero columns into |new_mask| at position
// |new_bit_index|. If the current byte of |new_mask| can't fit all zeros, the
// byte will be filled with zeros from |new_bit_index|, but the next byte will
// be untouched.
void InsertZeroColumns(int num_zeros,
uint8_t* new_mask,
int new_mask_bytes,
int num_fec_packets,
int new_bit_index);
// Copies the left most bit column from the byte pointed to by
// |old_bit_index| in |old_mask| to the right most column of the byte pointed
// to by |new_bit_index| in |new_mask|. |old_mask_bytes| and |new_mask_bytes|
// represent the number of bytes used per row for each mask. |num_fec_packets|
// represent the number of rows of the masks.
// The copied bit is shifted out from |old_mask| and is shifted one step to
// the left in |new_mask|. |new_mask| will contain "xxxx xxn0" after this
// operation, where x are previously inserted bits and n is the new bit.
void CopyColumn(uint8_t* new_mask,
int new_mask_bytes,
uint8_t* old_mask,
int old_mask_bytes,
int num_fec_packets,
int new_bit_index,
int old_bit_index);
} // namespace internal
} // namespace webrtc
#endif // WEBRTC_MODULES_RTP_RTCP_SOURCE_FORWARD_ERROR_CORRECTION_INTERNAL_H_