mirror of
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431 lines
16 KiB
C++
431 lines
16 KiB
C++
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/*
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* Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "webrtc/modules/audio_coding/neteq/payload_splitter.h"
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#include <assert.h>
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#include "webrtc/modules/audio_coding/neteq/decoder_database.h"
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namespace webrtc {
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// The method loops through a list of packets {A, B, C, ...}. Each packet is
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// split into its corresponding RED payloads, {A1, A2, ...}, which is
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// temporarily held in the list |new_packets|.
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// When the first packet in |packet_list| has been processed, the orignal packet
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// is replaced by the new ones in |new_packets|, so that |packet_list| becomes:
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// {A1, A2, ..., B, C, ...}. The method then continues with B, and C, until all
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// the original packets have been replaced by their split payloads.
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int PayloadSplitter::SplitRed(PacketList* packet_list) {
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int ret = kOK;
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PacketList::iterator it = packet_list->begin();
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while (it != packet_list->end()) {
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PacketList new_packets; // An empty list to store the split packets in.
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Packet* red_packet = (*it);
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assert(red_packet->payload);
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uint8_t* payload_ptr = red_packet->payload;
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// Read RED headers (according to RFC 2198):
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//
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// 0 1 2 3
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// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// |F| block PT | timestamp offset | block length |
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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// Last RED header:
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// 0 1 2 3 4 5 6 7
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// +-+-+-+-+-+-+-+-+
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// |0| Block PT |
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// +-+-+-+-+-+-+-+-+
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bool last_block = false;
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int sum_length = 0;
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while (!last_block) {
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Packet* new_packet = new Packet;
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new_packet->header = red_packet->header;
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// Check the F bit. If F == 0, this was the last block.
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last_block = ((*payload_ptr & 0x80) == 0);
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// Bits 1 through 7 are payload type.
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new_packet->header.payloadType = payload_ptr[0] & 0x7F;
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if (last_block) {
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// No more header data to read.
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++sum_length; // Account for RED header size of 1 byte.
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new_packet->payload_length = red_packet->payload_length - sum_length;
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new_packet->primary = true; // Last block is always primary.
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payload_ptr += 1; // Advance to first payload byte.
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} else {
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// Bits 8 through 21 are timestamp offset.
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int timestamp_offset = (payload_ptr[1] << 6) +
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((payload_ptr[2] & 0xFC) >> 2);
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new_packet->header.timestamp = red_packet->header.timestamp -
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timestamp_offset;
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// Bits 22 through 31 are payload length.
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new_packet->payload_length = ((payload_ptr[2] & 0x03) << 8) +
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payload_ptr[3];
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new_packet->primary = false;
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payload_ptr += 4; // Advance to next RED header.
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}
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sum_length += new_packet->payload_length;
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sum_length += 4; // Account for RED header size of 4 bytes.
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// Store in new list of packets.
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new_packets.push_back(new_packet);
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}
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// Populate the new packets with payload data.
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// |payload_ptr| now points at the first payload byte.
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PacketList::iterator new_it;
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for (new_it = new_packets.begin(); new_it != new_packets.end(); ++new_it) {
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int payload_length = (*new_it)->payload_length;
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if (payload_ptr + payload_length >
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red_packet->payload + red_packet->payload_length) {
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// The block lengths in the RED headers do not match the overall packet
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// length. Something is corrupt. Discard this and the remaining
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// payloads from this packet.
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while (new_it != new_packets.end()) {
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// Payload should not have been allocated yet.
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assert(!(*new_it)->payload);
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delete (*new_it);
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new_it = new_packets.erase(new_it);
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}
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ret = kRedLengthMismatch;
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break;
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}
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(*new_it)->payload = new uint8_t[payload_length];
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memcpy((*new_it)->payload, payload_ptr, payload_length);
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payload_ptr += payload_length;
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}
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// Reverse the order of the new packets, so that the primary payload is
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// always first.
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new_packets.reverse();
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// Insert new packets into original list, before the element pointed to by
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// iterator |it|.
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packet_list->splice(it, new_packets, new_packets.begin(),
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new_packets.end());
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// Delete old packet payload.
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delete [] (*it)->payload;
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delete (*it);
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// Remove |it| from the packet list. This operation effectively moves the
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// iterator |it| to the next packet in the list. Thus, we do not have to
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// increment it manually.
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it = packet_list->erase(it);
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}
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return ret;
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}
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int PayloadSplitter::SplitFec(PacketList* packet_list,
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DecoderDatabase* decoder_database) {
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PacketList::iterator it = packet_list->begin();
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// Iterate through all packets in |packet_list|.
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while (it != packet_list->end()) {
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Packet* packet = (*it); // Just to make the notation more intuitive.
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// Get codec type for this payload.
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uint8_t payload_type = packet->header.payloadType;
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const DecoderDatabase::DecoderInfo* info =
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decoder_database->GetDecoderInfo(payload_type);
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if (!info) {
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return kUnknownPayloadType;
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}
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// No splitting for a sync-packet.
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if (packet->sync_packet) {
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++it;
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continue;
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}
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// Not an FEC packet.
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AudioDecoder* decoder = decoder_database->GetDecoder(payload_type);
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// decoder should not return NULL.
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assert(decoder != NULL);
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if (!decoder ||
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!decoder->PacketHasFec(packet->payload, packet->payload_length)) {
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++it;
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continue;
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}
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switch (info->codec_type) {
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case kDecoderOpus:
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case kDecoderOpus_2ch: {
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Packet* new_packet = new Packet;
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new_packet->header = packet->header;
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int duration = decoder->
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PacketDurationRedundant(packet->payload, packet->payload_length);
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new_packet->header.timestamp -= duration;
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new_packet->payload = new uint8_t[packet->payload_length];
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memcpy(new_packet->payload, packet->payload, packet->payload_length);
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new_packet->payload_length = packet->payload_length;
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new_packet->primary = false;
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new_packet->waiting_time = packet->waiting_time;
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new_packet->sync_packet = packet->sync_packet;
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packet_list->insert(it, new_packet);
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break;
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}
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default: {
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return kFecSplitError;
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}
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}
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++it;
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}
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return kOK;
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}
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int PayloadSplitter::CheckRedPayloads(PacketList* packet_list,
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const DecoderDatabase& decoder_database) {
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PacketList::iterator it = packet_list->begin();
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int main_payload_type = -1;
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int num_deleted_packets = 0;
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while (it != packet_list->end()) {
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uint8_t this_payload_type = (*it)->header.payloadType;
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if (!decoder_database.IsDtmf(this_payload_type) &&
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!decoder_database.IsComfortNoise(this_payload_type)) {
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if (main_payload_type == -1) {
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// This is the first packet in the list which is non-DTMF non-CNG.
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main_payload_type = this_payload_type;
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} else {
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if (this_payload_type != main_payload_type) {
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// We do not allow redundant payloads of a different type.
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// Discard this payload.
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delete [] (*it)->payload;
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delete (*it);
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// Remove |it| from the packet list. This operation effectively
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// moves the iterator |it| to the next packet in the list. Thus, we
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// do not have to increment it manually.
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it = packet_list->erase(it);
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++num_deleted_packets;
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continue;
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}
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}
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}
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++it;
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}
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return num_deleted_packets;
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}
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int PayloadSplitter::SplitAudio(PacketList* packet_list,
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const DecoderDatabase& decoder_database) {
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PacketList::iterator it = packet_list->begin();
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// Iterate through all packets in |packet_list|.
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while (it != packet_list->end()) {
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Packet* packet = (*it); // Just to make the notation more intuitive.
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// Get codec type for this payload.
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const DecoderDatabase::DecoderInfo* info =
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decoder_database.GetDecoderInfo(packet->header.payloadType);
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if (!info) {
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return kUnknownPayloadType;
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}
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// No splitting for a sync-packet.
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if (packet->sync_packet) {
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++it;
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continue;
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}
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PacketList new_packets;
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switch (info->codec_type) {
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case kDecoderPCMu:
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case kDecoderPCMa: {
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// 8 bytes per ms; 8 timestamps per ms.
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SplitBySamples(packet, 8, 8, &new_packets);
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break;
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}
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case kDecoderPCMu_2ch:
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case kDecoderPCMa_2ch: {
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// 2 * 8 bytes per ms; 8 timestamps per ms.
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SplitBySamples(packet, 2 * 8, 8, &new_packets);
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break;
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}
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case kDecoderG722: {
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// 8 bytes per ms; 16 timestamps per ms.
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SplitBySamples(packet, 8, 16, &new_packets);
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break;
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}
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case kDecoderPCM16B: {
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// 16 bytes per ms; 8 timestamps per ms.
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SplitBySamples(packet, 16, 8, &new_packets);
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break;
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}
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case kDecoderPCM16Bwb: {
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// 32 bytes per ms; 16 timestamps per ms.
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SplitBySamples(packet, 32, 16, &new_packets);
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break;
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}
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case kDecoderPCM16Bswb32kHz: {
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// 64 bytes per ms; 32 timestamps per ms.
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SplitBySamples(packet, 64, 32, &new_packets);
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break;
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}
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case kDecoderPCM16Bswb48kHz: {
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// 96 bytes per ms; 48 timestamps per ms.
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SplitBySamples(packet, 96, 48, &new_packets);
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break;
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}
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case kDecoderPCM16B_2ch: {
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// 2 * 16 bytes per ms; 8 timestamps per ms.
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SplitBySamples(packet, 2 * 16, 8, &new_packets);
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break;
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}
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case kDecoderPCM16Bwb_2ch: {
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// 2 * 32 bytes per ms; 16 timestamps per ms.
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SplitBySamples(packet, 2 * 32, 16, &new_packets);
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break;
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}
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case kDecoderPCM16Bswb32kHz_2ch: {
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// 2 * 64 bytes per ms; 32 timestamps per ms.
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SplitBySamples(packet, 2 * 64, 32, &new_packets);
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break;
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}
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case kDecoderPCM16Bswb48kHz_2ch: {
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// 2 * 96 bytes per ms; 48 timestamps per ms.
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SplitBySamples(packet, 2 * 96, 48, &new_packets);
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break;
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}
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case kDecoderPCM16B_5ch: {
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// 5 * 16 bytes per ms; 8 timestamps per ms.
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SplitBySamples(packet, 5 * 16, 8, &new_packets);
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break;
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}
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case kDecoderILBC: {
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int bytes_per_frame;
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int timestamps_per_frame;
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if (packet->payload_length >= 950) {
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return kTooLargePayload;
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} else if (packet->payload_length % 38 == 0) {
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// 20 ms frames.
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bytes_per_frame = 38;
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timestamps_per_frame = 160;
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} else if (packet->payload_length % 50 == 0) {
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// 30 ms frames.
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bytes_per_frame = 50;
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timestamps_per_frame = 240;
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} else {
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return kFrameSplitError;
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}
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int ret = SplitByFrames(packet, bytes_per_frame, timestamps_per_frame,
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&new_packets);
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if (ret < 0) {
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return ret;
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} else if (ret == kNoSplit) {
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// Do not split at all. Simply advance to the next packet in the list.
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++it;
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// We do not have any new packets to insert, and should not delete the
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// old one. Skip the code after the switch case, and jump straight to
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// the next packet in the while loop.
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continue;
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}
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break;
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}
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default: {
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// Do not split at all. Simply advance to the next packet in the list.
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++it;
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// We do not have any new packets to insert, and should not delete the
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// old one. Skip the code after the switch case, and jump straight to
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// the next packet in the while loop.
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continue;
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}
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}
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// Insert new packets into original list, before the element pointed to by
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// iterator |it|.
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packet_list->splice(it, new_packets, new_packets.begin(),
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new_packets.end());
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// Delete old packet payload.
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delete [] (*it)->payload;
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delete (*it);
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// Remove |it| from the packet list. This operation effectively moves the
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// iterator |it| to the next packet in the list. Thus, we do not have to
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// increment it manually.
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it = packet_list->erase(it);
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}
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return kOK;
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}
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void PayloadSplitter::SplitBySamples(const Packet* packet,
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int bytes_per_ms,
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int timestamps_per_ms,
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PacketList* new_packets) {
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assert(packet);
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assert(new_packets);
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int split_size_bytes = packet->payload_length;
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// Find a "chunk size" >= 20 ms and < 40 ms.
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int min_chunk_size = bytes_per_ms * 20;
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// Reduce the split size by half as long as |split_size_bytes| is at least
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// twice the minimum chunk size (so that the resulting size is at least as
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// large as the minimum chunk size).
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while (split_size_bytes >= 2 * min_chunk_size) {
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split_size_bytes >>= 1;
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}
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int timestamps_per_chunk =
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split_size_bytes * timestamps_per_ms / bytes_per_ms;
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uint32_t timestamp = packet->header.timestamp;
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uint8_t* payload_ptr = packet->payload;
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int len = packet->payload_length;
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while (len >= (2 * split_size_bytes)) {
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Packet* new_packet = new Packet;
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new_packet->payload_length = split_size_bytes;
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new_packet->header = packet->header;
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new_packet->header.timestamp = timestamp;
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timestamp += timestamps_per_chunk;
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new_packet->primary = packet->primary;
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new_packet->payload = new uint8_t[split_size_bytes];
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memcpy(new_packet->payload, payload_ptr, split_size_bytes);
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payload_ptr += split_size_bytes;
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new_packets->push_back(new_packet);
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len -= split_size_bytes;
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}
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if (len > 0) {
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Packet* new_packet = new Packet;
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new_packet->payload_length = len;
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new_packet->header = packet->header;
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new_packet->header.timestamp = timestamp;
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new_packet->primary = packet->primary;
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new_packet->payload = new uint8_t[len];
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memcpy(new_packet->payload, payload_ptr, len);
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new_packets->push_back(new_packet);
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}
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}
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int PayloadSplitter::SplitByFrames(const Packet* packet,
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int bytes_per_frame,
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int timestamps_per_frame,
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PacketList* new_packets) {
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if (packet->payload_length % bytes_per_frame != 0) {
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return kFrameSplitError;
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}
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int num_frames = packet->payload_length / bytes_per_frame;
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if (num_frames == 1) {
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// Special case. Do not split the payload.
|
||
|
return kNoSplit;
|
||
|
}
|
||
|
|
||
|
uint32_t timestamp = packet->header.timestamp;
|
||
|
uint8_t* payload_ptr = packet->payload;
|
||
|
int len = packet->payload_length;
|
||
|
while (len > 0) {
|
||
|
assert(len >= bytes_per_frame);
|
||
|
Packet* new_packet = new Packet;
|
||
|
new_packet->payload_length = bytes_per_frame;
|
||
|
new_packet->header = packet->header;
|
||
|
new_packet->header.timestamp = timestamp;
|
||
|
timestamp += timestamps_per_frame;
|
||
|
new_packet->primary = packet->primary;
|
||
|
new_packet->payload = new uint8_t[bytes_per_frame];
|
||
|
memcpy(new_packet->payload, payload_ptr, bytes_per_frame);
|
||
|
payload_ptr += bytes_per_frame;
|
||
|
new_packets->push_back(new_packet);
|
||
|
len -= bytes_per_frame;
|
||
|
}
|
||
|
return kOK;
|
||
|
}
|
||
|
|
||
|
} // namespace webrtc
|