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https://gitlab.freedesktop.org/pipewire/pipewire.git
synced 2025-10-29 05:40:27 -04:00
sco-source: simplify mSBC frame parsing
Simplify mSBC buffer handling and syncing to frame headers to work on a per-byte basis. The previous code could terminate with buffer overrun if it encountered multiple consecutive incomplete packets.
This commit is contained in:
Pauli Virtanen
Wim Taymans
parent
2760c151bd
commit
a5e52c07b1
1 changed files with 90 additions and 91 deletions
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@ -58,7 +58,6 @@ struct props {
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};
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#define MAX_BUFFERS 32
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#define MSBC_BUFFER_SIZE 2 * MSBC_ENCODED_SIZE
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struct buffer {
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uint32_t id;
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@ -121,9 +120,11 @@ struct impl {
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sbc_t msbc;
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bool msbc_seq_initialized;
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uint8_t msbc_seq;
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uint8_t msbc_buffer[MSBC_BUFFER_SIZE];
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uint8_t *msbc_buffer_head;
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uint8_t *msbc_buffer_tail;
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uint8_t read_buffer[4096];
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/* mSBC frame parsing */
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uint8_t msbc_buffer[MSBC_ENCODED_SIZE];
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uint8_t msbc_buffer_pos;
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struct timespec now;
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};
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@ -316,29 +317,51 @@ static void recycle_buffer(struct impl *this, struct port *port, uint32_t buffer
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}
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}
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static uint8_t* find_h2_header(uint8_t *data, size_t len)
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/* Append data to msbc buffer, syncing buffer start to frame headers */
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static void msbc_buffer_append_byte(struct impl *this, uint8_t byte)
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{
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while (len >= 2) {
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if (data[0] == 0x01 && (data[1] & 0x0F) == 0x08 &&
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((data[1] >> 4) & 1) == ((data[1] >> 5) & 1) &&
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((data[1] >> 6) & 1) == ((data[1] >> 7) & 1) ) {
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return data;
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}
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data++;
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len--;
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}
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return NULL;
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}
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/* Compact msbc_buffer to keep it under 2 * MSBC_ENCODED_SIZE */
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void compact_msbc_buffer(struct impl *this, uint8_t *tail, uint8_t *head) {
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if (head != tail) {
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spa_memmove(this->msbc_buffer, tail, head - tail);
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this->msbc_buffer_head = this->msbc_buffer + (head - tail);
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this->msbc_buffer_tail = this->msbc_buffer;
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} else
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this->msbc_buffer_head = this->msbc_buffer_tail = this->msbc_buffer;
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/* Parse mSBC frame header */
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if (this->msbc_buffer_pos == 0) {
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if (byte != 0x01) {
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this->msbc_buffer_pos = 0;
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return;
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}
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}
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else if (this->msbc_buffer_pos == 1) {
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if (!((byte & 0x0F) == 0x08 &&
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((byte >> 4) & 1) == ((byte >> 5) & 1) &&
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((byte >> 6) & 1) == ((byte >> 7) & 1))) {
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this->msbc_buffer_pos = 0;
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return;
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}
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}
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else if (this->msbc_buffer_pos == 2) {
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/* .. and beginning of MSBC frame: SYNCWORD + 2 nul bytes */
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if (byte != 0xAD) {
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this->msbc_buffer_pos = 0;
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return;
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}
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}
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else if (this->msbc_buffer_pos == 3) {
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if (byte != 0x00) {
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this->msbc_buffer_pos = 0;
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return;
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}
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}
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else if (this->msbc_buffer_pos == 4) {
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if (byte != 0x00) {
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this->msbc_buffer_pos = 0;
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return;
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}
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}
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else if (this->msbc_buffer_pos >= MSBC_ENCODED_SIZE) {
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/* Packet completed. Reset. */
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this->msbc_buffer_pos = 0;
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msbc_buffer_append_byte(this, byte);
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return;
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}
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this->msbc_buffer[this->msbc_buffer_pos] = byte;
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++this->msbc_buffer_pos;
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}
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static void sco_on_ready_read(struct spa_source *source)
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@ -375,7 +398,7 @@ static void sco_on_ready_read(struct spa_source *source)
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if (this->transport->codec == HFP_AUDIO_CODEC_MSBC) {
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max_out_size = MSBC_DECODED_SIZE;
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packet = this->msbc_buffer_head;
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packet = this->read_buffer;
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} else {
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max_out_size = this->transport->read_mtu;
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packet = (uint8_t *)datas[0].data + port->ready_offset;
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@ -393,71 +416,45 @@ static void sco_on_ready_read(struct spa_source *source)
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spa_log_debug(this->log, "read socket data %d", size_read);
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if (this->transport->codec == HFP_AUDIO_CODEC_MSBC) {
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uint8_t seq;
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uint8_t *next_header;
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size_t written;
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int i;
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this->msbc_buffer_head += size_read;
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if (this->msbc_buffer_head - this->msbc_buffer >= MSBC_BUFFER_SIZE) {
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spa_log_error(this->log, "buffer overrun");
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goto stop;
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for (i = 0; i < size_read; ++i) {
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msbc_buffer_append_byte(this, packet[i]);
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/* Handle found mSBC packets.
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*
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* XXX: if there's no space for the decoded audio in
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* XXX: the current buffer, we'll drop data.
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*/
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if (this->msbc_buffer_pos == MSBC_ENCODED_SIZE &&
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port->ready_offset + MSBC_DECODED_SIZE <= datas[0].maxsize) {
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int seq, processed;
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size_t written;
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/* Check sequence number */
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seq = ((this->msbc_buffer[1] >> 4) & 1) | ((this->msbc_buffer[1] >> 6) & 2);
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if (!this->msbc_seq_initialized) {
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this->msbc_seq_initialized = true;
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this->msbc_seq = seq;
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} else if (seq != this->msbc_seq) {
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spa_log_info(this->log, "missing mSBC packet: %u != %u", seq, this->msbc_seq);
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this->msbc_seq = seq;
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/* TODO: Implement PLC. */
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}
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this->msbc_seq = (this->msbc_seq + 1) % 4;
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/* decode frame */
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processed = sbc_decode(&this->msbc, this->msbc_buffer + 2, MSBC_ENCODED_SIZE - 3,
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(uint8_t *)datas[0].data + port->ready_offset, MSBC_DECODED_SIZE, &written);
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if (processed < 0) {
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spa_log_warn(this->log, "sbc_decode failed: %d", processed);
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/* TODO: manage errors */
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continue;
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}
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port->ready_offset += written;
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}
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}
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this->msbc_buffer_tail = find_h2_header(this->msbc_buffer_tail, this->msbc_buffer_head - this->msbc_buffer_tail);
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if (!this->msbc_buffer_tail) {
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this->msbc_buffer_head = this->msbc_buffer_tail = this->msbc_buffer;
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spa_log_trace(this->log, "void packet");
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return;
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}
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/* We might discard up to MTU - 2 bytes. If MTU = 48, we might need two
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more packets to get MSBC_ENCODED_SIZE valid bytes. Therefore, without
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compacting here we would need MSBC_BUFFER_SIZE >= 3*MTU - 2. In practice,
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for MTU = 48, we frequently need MSBC_BUFFER_SIZE >= 132. */
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compact_msbc_buffer(this, this->msbc_buffer_tail, this->msbc_buffer_head);
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if (this->msbc_buffer_head - this->msbc_buffer_tail < MSBC_ENCODED_SIZE) {
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spa_log_trace(this->log, "partial packet");
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return;
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}
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next_header = find_h2_header(this->msbc_buffer_tail + 2, this->msbc_buffer_head - this->msbc_buffer_tail - 2);
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if (next_header && (next_header - this->msbc_buffer_tail) != MSBC_ENCODED_SIZE) {
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spa_log_trace(this->log, "incomplete packet");
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this->msbc_seq = (this->msbc_seq + 1) % 4;
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/* Drop the incomplete packet and compact */
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compact_msbc_buffer(this, next_header, this->msbc_buffer_head);
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/* TODO: Implement PLC? */
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return;
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}
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seq = ((this->msbc_buffer_tail[1] >> 4) & 1) | ((this->msbc_buffer_tail[1] >> 6) & 2);
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if (!this->msbc_seq_initialized) {
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this->msbc_seq_initialized = true;
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this->msbc_seq = seq;
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} else if (seq != this->msbc_seq) {
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spa_log_warn(this->log, "missing mSBC packet: %u != %u", seq, this->msbc_seq);
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this->msbc_seq = seq;
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/* TODO: Implement PLC. */
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}
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/* decode frame */
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int processed = sbc_decode(&this->msbc, this->msbc_buffer_tail + 2, MSBC_ENCODED_SIZE - 3,
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(uint8_t *)datas[0].data + port->ready_offset, MSBC_DECODED_SIZE, &written);
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if (processed < 0) {
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spa_log_warn(this->log, "sbc_decode failed: %d", processed);
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/* TODO: manage errors */
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this->msbc_buffer_tail += MSBC_ENCODED_SIZE;
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compact_msbc_buffer(this, this->msbc_buffer_tail, this->msbc_buffer_head);
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return;
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}
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port->ready_offset += written;
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this->msbc_seq = (this->msbc_seq + 1) % 4;
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this->msbc_buffer_tail += MSBC_ENCODED_SIZE;
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compact_msbc_buffer(this, this->msbc_buffer_tail, this->msbc_buffer_head);
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} else
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port->ready_offset += size_read;
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@ -539,7 +536,9 @@ static int do_start(struct impl *this)
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/* Libsbc expects audio samples by default in host endianity, mSBC requires little endian */
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this->msbc.endian = SBC_LE;
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this->msbc_seq_initialized = false;
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this->msbc_buffer_head = this->msbc_buffer_tail = this->msbc_buffer;
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this->msbc_buffer_pos = 0;
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spa_assert(this->transport->read_mtu <= sizeof(this->read_buffer));
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}
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/* Add the ready read callback */
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