src/modules/audio_coding/neteq/rtp.c - vendor/opensource/webrtc - Git at Google

 /*
  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */

 /*
  * RTP related functions.
  */

 #include "rtp.h"

 #include "typedefs.h" /* to define endianness */

 #include "neteq_error_codes.h"

 int WebRtcNetEQ_RTPPayloadInfo(WebRtc_Word16* pw16_Datagram, int i_DatagramLen,
                                RTPPacket_t* RTPheader)
 {
     int i_P, i_X, i_CC, i_startPosition;
     int i_IPver;
     int i_extlength = -1; /* Default value is there is no extension */
     int i_padlength = 0; /* Default value if there is no padding */

     if (i_DatagramLen < 12)
     {
         return RTP_TOO_SHORT_PACKET;
     }

 #ifdef WEBRTC_BIG_ENDIAN
     i_IPver = (((WebRtc_UWord16) (pw16_Datagram[0] & 0xC000)) >> 14); /* Extract the version */
     i_P = (((WebRtc_UWord16) (pw16_Datagram[0] & 0x2000)) >> 13); /* Extract the P bit */
     i_X = (((WebRtc_UWord16) (pw16_Datagram[0] & 0x1000)) >> 12); /* Extract the X bit */
     i_CC = ((WebRtc_UWord16) (pw16_Datagram[0] >> 8) & 0xF); /* Get the CC number */
     RTPheader->payloadType = pw16_Datagram[0] & 0x7F; /* Get the coder type	*/
     RTPheader->seqNumber = pw16_Datagram[1]; /* Get the sequence number	*/
     RTPheader->timeStamp = ((((WebRtc_UWord32) ((WebRtc_UWord16) pw16_Datagram[2])) << 16)
         | (WebRtc_UWord16) (pw16_Datagram[3])); /* Get timestamp */
     RTPheader->ssrc = (((WebRtc_UWord32) pw16_Datagram[4]) << 16)
         + (((WebRtc_UWord32) pw16_Datagram[5])); /* Get the SSRC */

     if (i_X == 1)
     {
         /* Extension header exists. Find out how many WebRtc_Word32 it consists of. */
         i_extlength = pw16_Datagram[7 + 2 * i_CC];
     }
     if (i_P == 1)
     {
         /* Padding exists. Find out how many bytes the padding consists of. */
         if (i_DatagramLen & 0x1)
         {
             /* odd number of bytes => last byte in higher byte */
             i_padlength = (((WebRtc_UWord16) pw16_Datagram[i_DatagramLen >> 1]) >> 8);
         }
         else
         {
             /* even number of bytes => last byte in lower byte */
             i_padlength = ((pw16_Datagram[(i_DatagramLen >> 1) - 1]) & 0xFF);
         }
     }
 #else /* WEBRTC_LITTLE_ENDIAN */
     i_IPver = (((WebRtc_UWord16) (pw16_Datagram[0] & 0xC0)) >> 6); /* Extract the IP version */
     i_P = (((WebRtc_UWord16) (pw16_Datagram[0] & 0x20)) >> 5); /* Extract the P bit */
     i_X = (((WebRtc_UWord16) (pw16_Datagram[0] & 0x10)) >> 4); /* Extract the X bit */
     i_CC = (WebRtc_UWord16) (pw16_Datagram[0] & 0xF); /* Get the CC number */
     RTPheader->payloadType = (pw16_Datagram[0] >> 8) & 0x7F; /* Get the coder type */
     RTPheader->seqNumber = (((((WebRtc_UWord16) pw16_Datagram[1]) >> 8) & 0xFF)
         | (((WebRtc_UWord16) (pw16_Datagram[1] & 0xFF)) << 8)); /* Get the packet number */
     RTPheader->timeStamp = ((((WebRtc_UWord16) pw16_Datagram[2]) & 0xFF) << 24)
         | ((((WebRtc_UWord16) pw16_Datagram[2]) & 0xFF00) << 8)
         | ((((WebRtc_UWord16) pw16_Datagram[3]) >> 8) & 0xFF)
         | ((((WebRtc_UWord16) pw16_Datagram[3]) & 0xFF) << 8); /* Get timestamp */
     RTPheader->ssrc = ((((WebRtc_UWord16) pw16_Datagram[4]) & 0xFF) << 24)
         | ((((WebRtc_UWord16) pw16_Datagram[4]) & 0xFF00) << 8)
         | ((((WebRtc_UWord16) pw16_Datagram[5]) >> 8) & 0xFF)
         | ((((WebRtc_UWord16) pw16_Datagram[5]) & 0xFF) << 8); /* Get the SSRC */

     if (i_X == 1)
     {
         /* Extension header exists. Find out how many WebRtc_Word32 it consists of. */
         i_extlength = (((((WebRtc_UWord16) pw16_Datagram[7 + 2 * i_CC]) >> 8) & 0xFF)
             | (((WebRtc_UWord16) (pw16_Datagram[7 + 2 * i_CC] & 0xFF)) << 8));
     }
     if (i_P == 1)
     {
         /* Padding exists. Find out how many bytes the padding consists of. */
         if (i_DatagramLen & 0x1)
         {
             /* odd number of bytes => last byte in higher byte */
             i_padlength = (pw16_Datagram[i_DatagramLen >> 1] & 0xFF);
         }
         else
         {
             /* even number of bytes => last byte in lower byte */
             i_padlength = (((WebRtc_UWord16) pw16_Datagram[(i_DatagramLen >> 1) - 1]) >> 8);
         }
     }
 #endif

     i_startPosition = 12 + 4 * (i_extlength + 1) + 4 * i_CC;
     RTPheader->payload = &pw16_Datagram[i_startPosition >> 1];
     RTPheader->payloadLen = i_DatagramLen - i_startPosition - i_padlength;
     RTPheader->starts_byte1 = 0;

     if ((i_IPver != 2) || (RTPheader->payloadLen <= 0) || (RTPheader->payloadLen >= 16000)
         || (i_startPosition < 12) || (i_startPosition > i_DatagramLen))
     {
         return RTP_CORRUPT_PACKET;
     }

     return 0;
 }

 #ifdef NETEQ_RED_CODEC

 int WebRtcNetEQ_RedundancySplit(RTPPacket_t* RTPheader[], int i_MaximumPayloads,
                                 int *i_No_Of_Payloads)
 {
     const WebRtc_Word16 *pw16_data = RTPheader[0]->payload; /* Pointer to the data */
     WebRtc_UWord16 uw16_offsetTimeStamp = 65535, uw16_secondPayload = 65535;
     int i_blockLength, i_k;
     int i_discardedBlockLength = 0;
     int singlePayload = 0;

 #ifdef WEBRTC_BIG_ENDIAN
     if ((pw16_data[0] & 0x8000) == 0)
     {
         /* Only one payload in this packet*/
         singlePayload = 1;
         /* set the blocklength to -4 to deduce the non-existent 4-byte RED header */
         i_blockLength = -4;
         RTPheader[0]->payloadType = ((((WebRtc_UWord16)pw16_data[0]) & 0x7F00) >> 8);
     }
     else
     {
         /* Discard all but the two last payloads. */
         while (((pw16_data[2] & 0x8000) == 1)&&
             (pw16_data<((RTPheader[0]->payload)+((RTPheader[0]->payloadLen+1)>>1))))
         {
             i_discardedBlockLength += (4+(((WebRtc_UWord16)pw16_data[1]) & 0x3FF));
             pw16_data+=2;
         }
         if (pw16_data>=(RTPheader[0]->payload+((RTPheader[0]->payloadLen+1)>>1)))
         {
             return RED_SPLIT_ERROR2; /* Error, we are outside the packet */
         }
         singlePayload = 0; /* the packet contains more than one payload */
         uw16_secondPayload = ((((WebRtc_UWord16)pw16_data[0]) & 0x7F00) >> 8);
         RTPheader[0]->payloadType = ((((WebRtc_UWord16)pw16_data[2]) & 0x7F00) >> 8);
         uw16_offsetTimeStamp = ((((WebRtc_UWord16)pw16_data[0]) & 0xFF) << 6) +
         ((((WebRtc_UWord16)pw16_data[1]) & 0xFC00) >> 10);
         i_blockLength = (((WebRtc_UWord16)pw16_data[1]) & 0x3FF);
     }
 #else /* WEBRTC_LITTLE_ENDIAN */
     if ((pw16_data[0] & 0x80) == 0)
     {
         /* Only one payload in this packet */
         singlePayload = 1;
         /* set the blocklength to -4 to deduce the non-existent 4-byte RED header */
         i_blockLength = -4;
         RTPheader[0]->payloadType = (((WebRtc_UWord16) pw16_data[0]) & 0x7F);
     }
     else
     {
         /* Discard all but the two last payloads. */
         while (((pw16_data[2] & 0x80) == 1) && (pw16_data < ((RTPheader[0]->payload)
             + ((RTPheader[0]->payloadLen + 1) >> 1))))
         {
             i_discardedBlockLength += (4 + ((((WebRtc_UWord16) pw16_data[1]) & 0x3) << 8)
                 + ((((WebRtc_UWord16) pw16_data[1]) & 0xFF00) >> 8));
             pw16_data += 2;
         }
         if (pw16_data >= (RTPheader[0]->payload + ((RTPheader[0]->payloadLen + 1) >> 1)))
         {
             return RED_SPLIT_ERROR2; /* Error, we are outside the packet */;
         }
         singlePayload = 0; /* the packet contains more than one payload */
         uw16_secondPayload = (((WebRtc_UWord16) pw16_data[0]) & 0x7F);
         RTPheader[0]->payloadType = (((WebRtc_UWord16) pw16_data[2]) & 0x7F);
         uw16_offsetTimeStamp = ((((WebRtc_UWord16) pw16_data[0]) & 0xFF00) >> 2)
             + ((((WebRtc_UWord16) pw16_data[1]) & 0xFC) >> 2);
         i_blockLength = ((((WebRtc_UWord16) pw16_data[1]) & 0x3) << 8)
             + ((((WebRtc_UWord16) pw16_data[1]) & 0xFF00) >> 8);
     }
 #endif

     if (i_MaximumPayloads < 2 || singlePayload == 1)
     {
         /* Reject the redundancy; or no redundant payload present. */
         for (i_k = 1; i_k < i_MaximumPayloads; i_k++)
         {
             RTPheader[i_k]->payloadType = -1;
             RTPheader[i_k]->payloadLen = 0;
         }

         /* update the pointer for the main data */
         pw16_data = &pw16_data[(5 + i_blockLength) >> 1];
         RTPheader[0]->starts_byte1 = (5 + i_blockLength) & 0x1;
         RTPheader[0]->payloadLen = RTPheader[0]->payloadLen - (i_blockLength + 5)
             - i_discardedBlockLength;
         RTPheader[0]->payload = pw16_data;

         *i_No_Of_Payloads = 1;

     }
     else
     {
         /* Redundancy accepted, put the redundancy in second RTPheader. */
         RTPheader[1]->payloadType = uw16_secondPayload;
         RTPheader[1]->payload = &pw16_data[5 >> 1];
         RTPheader[1]->starts_byte1 = 5 & 0x1;
         RTPheader[1]->seqNumber = RTPheader[0]->seqNumber;
         RTPheader[1]->timeStamp = RTPheader[0]->timeStamp - uw16_offsetTimeStamp;
         RTPheader[1]->ssrc = RTPheader[0]->ssrc;
         RTPheader[1]->payloadLen = i_blockLength;

         /* Modify first RTP packet, so that it contains the main data. */
         RTPheader[0]->payload = &pw16_data[(5 + i_blockLength) >> 1];
         RTPheader[0]->starts_byte1 = (5 + i_blockLength) & 0x1;
         RTPheader[0]->payloadLen = RTPheader[0]->payloadLen - (i_blockLength + 5)
             - i_discardedBlockLength;

         /* Clear the following payloads. */
         for (i_k = 2; i_k < i_MaximumPayloads; i_k++)
         {
             RTPheader[i_k]->payloadType = -1;
             RTPheader[i_k]->payloadLen = 0;
         }

         *i_No_Of_Payloads = 2;
     }
     return 0;
 }

 #endif
	/*
	* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
	*
	* Use of this source code is governed by a BSD-style license
	* that can be found in the LICENSE file in the root of the source
	* tree. An additional intellectual property rights grant can be found
	* in the file PATENTS. All contributing project authors may
	* be found in the AUTHORS file in the root of the source tree.
	*/

	/*
	* RTP related functions.
	*/

	#include "rtp.h"

	#include "typedefs.h" /* to define endianness */

	#include "neteq_error_codes.h"

	int WebRtcNetEQ_RTPPayloadInfo(WebRtc_Word16* pw16_Datagram, int i_DatagramLen,
	RTPPacket_t* RTPheader)
	{
	int i_P, i_X, i_CC, i_startPosition;
	int i_IPver;
	int i_extlength = -1; /* Default value is there is no extension */
	int i_padlength = 0; /* Default value if there is no padding */

	if (i_DatagramLen < 12)
	{
	return RTP_TOO_SHORT_PACKET;
	}

	#ifdef WEBRTC_BIG_ENDIAN
	i_IPver = (((WebRtc_UWord16) (pw16_Datagram[0] & 0xC000)) >> 14); /* Extract the version */
	i_P = (((WebRtc_UWord16) (pw16_Datagram[0] & 0x2000)) >> 13); /* Extract the P bit */
	i_X = (((WebRtc_UWord16) (pw16_Datagram[0] & 0x1000)) >> 12); /* Extract the X bit */
	i_CC = ((WebRtc_UWord16) (pw16_Datagram[0] >> 8) & 0xF); /* Get the CC number */
	RTPheader->payloadType = pw16_Datagram[0] & 0x7F; /* Get the coder type */
	RTPheader->seqNumber = pw16_Datagram[1]; /* Get the sequence number */
	RTPheader->timeStamp = ((((WebRtc_UWord32) ((WebRtc_UWord16) pw16_Datagram[2])) << 16)
	\| (WebRtc_UWord16) (pw16_Datagram[3])); /* Get timestamp */
	RTPheader->ssrc = (((WebRtc_UWord32) pw16_Datagram[4]) << 16)
	+ (((WebRtc_UWord32) pw16_Datagram[5])); /* Get the SSRC */

	if (i_X == 1)
	{
	/* Extension header exists. Find out how many WebRtc_Word32 it consists of. */
	i_extlength = pw16_Datagram[7 + 2 * i_CC];
	}
	if (i_P == 1)
	{
	/* Padding exists. Find out how many bytes the padding consists of. */
	if (i_DatagramLen & 0x1)
	{
	/* odd number of bytes => last byte in higher byte */
	i_padlength = (((WebRtc_UWord16) pw16_Datagram[i_DatagramLen >> 1]) >> 8);
	}
	else
	{
	/* even number of bytes => last byte in lower byte */
	i_padlength = ((pw16_Datagram[(i_DatagramLen >> 1) - 1]) & 0xFF);
	}
	}
	#else /* WEBRTC_LITTLE_ENDIAN */
	i_IPver = (((WebRtc_UWord16) (pw16_Datagram[0] & 0xC0)) >> 6); /* Extract the IP version */
	i_P = (((WebRtc_UWord16) (pw16_Datagram[0] & 0x20)) >> 5); /* Extract the P bit */
	i_X = (((WebRtc_UWord16) (pw16_Datagram[0] & 0x10)) >> 4); /* Extract the X bit */
	i_CC = (WebRtc_UWord16) (pw16_Datagram[0] & 0xF); /* Get the CC number */
	RTPheader->payloadType = (pw16_Datagram[0] >> 8) & 0x7F; /* Get the coder type */
	RTPheader->seqNumber = (((((WebRtc_UWord16) pw16_Datagram[1]) >> 8) & 0xFF)
	\| (((WebRtc_UWord16) (pw16_Datagram[1] & 0xFF)) << 8)); /* Get the packet number */
	RTPheader->timeStamp = ((((WebRtc_UWord16) pw16_Datagram[2]) & 0xFF) << 24)
	\| ((((WebRtc_UWord16) pw16_Datagram[2]) & 0xFF00) << 8)
	\| ((((WebRtc_UWord16) pw16_Datagram[3]) >> 8) & 0xFF)
	\| ((((WebRtc_UWord16) pw16_Datagram[3]) & 0xFF) << 8); /* Get timestamp */
	RTPheader->ssrc = ((((WebRtc_UWord16) pw16_Datagram[4]) & 0xFF) << 24)
	\| ((((WebRtc_UWord16) pw16_Datagram[4]) & 0xFF00) << 8)
	\| ((((WebRtc_UWord16) pw16_Datagram[5]) >> 8) & 0xFF)
	\| ((((WebRtc_UWord16) pw16_Datagram[5]) & 0xFF) << 8); /* Get the SSRC */

	if (i_X == 1)
	{
	/* Extension header exists. Find out how many WebRtc_Word32 it consists of. */
	i_extlength = (((((WebRtc_UWord16) pw16_Datagram[7 + 2 * i_CC]) >> 8) & 0xFF)
	\| (((WebRtc_UWord16) (pw16_Datagram[7 + 2 * i_CC] & 0xFF)) << 8));
	}
	if (i_P == 1)
	{
	/* Padding exists. Find out how many bytes the padding consists of. */
	if (i_DatagramLen & 0x1)
	{
	/* odd number of bytes => last byte in higher byte */
	i_padlength = (pw16_Datagram[i_DatagramLen >> 1] & 0xFF);
	}
	else
	{
	/* even number of bytes => last byte in lower byte */
	i_padlength = (((WebRtc_UWord16) pw16_Datagram[(i_DatagramLen >> 1) - 1]) >> 8);
	}
	}
	#endif

	i_startPosition = 12 + 4 * (i_extlength + 1) + 4 * i_CC;
	RTPheader->payload = &pw16_Datagram[i_startPosition >> 1];
	RTPheader->payloadLen = i_DatagramLen - i_startPosition - i_padlength;
	RTPheader->starts_byte1 = 0;

	if ((i_IPver != 2) \|\| (RTPheader->payloadLen <= 0) \|\| (RTPheader->payloadLen >= 16000)
	\|\| (i_startPosition < 12) \|\| (i_startPosition > i_DatagramLen))
	{
	return RTP_CORRUPT_PACKET;
	}

	return 0;
	}

	#ifdef NETEQ_RED_CODEC

	int WebRtcNetEQ_RedundancySplit(RTPPacket_t* RTPheader[], int i_MaximumPayloads,
	int *i_No_Of_Payloads)
	{
	const WebRtc_Word16 pw16_data = RTPheader[0]->payload; / Pointer to the data */
	WebRtc_UWord16 uw16_offsetTimeStamp = 65535, uw16_secondPayload = 65535;
	int i_blockLength, i_k;
	int i_discardedBlockLength = 0;
	int singlePayload = 0;

	#ifdef WEBRTC_BIG_ENDIAN
	if ((pw16_data[0] & 0x8000) == 0)
	{
	/* Only one payload in this packet*/
	singlePayload = 1;
	/* set the blocklength to -4 to deduce the non-existent 4-byte RED header */
	i_blockLength = -4;
	RTPheader[0]->payloadType = ((((WebRtc_UWord16)pw16_data[0]) & 0x7F00) >> 8);
	}
	else
	{
	/* Discard all but the two last payloads. */
	while (((pw16_data[2] & 0x8000) == 1)&&
	(pw16_data<((RTPheader[0]->payload)+((RTPheader[0]->payloadLen+1)>>1))))
	{
	i_discardedBlockLength += (4+(((WebRtc_UWord16)pw16_data[1]) & 0x3FF));
	pw16_data+=2;
	}
	if (pw16_data>=(RTPheader[0]->payload+((RTPheader[0]->payloadLen+1)>>1)))
	{
	return RED_SPLIT_ERROR2; /* Error, we are outside the packet */
	}
	singlePayload = 0; /* the packet contains more than one payload */
	uw16_secondPayload = ((((WebRtc_UWord16)pw16_data[0]) & 0x7F00) >> 8);
	RTPheader[0]->payloadType = ((((WebRtc_UWord16)pw16_data[2]) & 0x7F00) >> 8);
	uw16_offsetTimeStamp = ((((WebRtc_UWord16)pw16_data[0]) & 0xFF) << 6) +
	((((WebRtc_UWord16)pw16_data[1]) & 0xFC00) >> 10);
	i_blockLength = (((WebRtc_UWord16)pw16_data[1]) & 0x3FF);
	}
	#else /* WEBRTC_LITTLE_ENDIAN */
	if ((pw16_data[0] & 0x80) == 0)
	{
	/* Only one payload in this packet */
	singlePayload = 1;
	/* set the blocklength to -4 to deduce the non-existent 4-byte RED header */
	i_blockLength = -4;
	RTPheader[0]->payloadType = (((WebRtc_UWord16) pw16_data[0]) & 0x7F);
	}
	else
	{
	/* Discard all but the two last payloads. */
	while (((pw16_data[2] & 0x80) == 1) && (pw16_data < ((RTPheader[0]->payload)
	+ ((RTPheader[0]->payloadLen + 1) >> 1))))
	{
	i_discardedBlockLength += (4 + ((((WebRtc_UWord16) pw16_data[1]) & 0x3) << 8)
	+ ((((WebRtc_UWord16) pw16_data[1]) & 0xFF00) >> 8));
	pw16_data += 2;
	}
	if (pw16_data >= (RTPheader[0]->payload + ((RTPheader[0]->payloadLen + 1) >> 1)))
	{
	return RED_SPLIT_ERROR2; /* Error, we are outside the packet */;
	}
	singlePayload = 0; /* the packet contains more than one payload */
	uw16_secondPayload = (((WebRtc_UWord16) pw16_data[0]) & 0x7F);
	RTPheader[0]->payloadType = (((WebRtc_UWord16) pw16_data[2]) & 0x7F);
	uw16_offsetTimeStamp = ((((WebRtc_UWord16) pw16_data[0]) & 0xFF00) >> 2)
	+ ((((WebRtc_UWord16) pw16_data[1]) & 0xFC) >> 2);
	i_blockLength = ((((WebRtc_UWord16) pw16_data[1]) & 0x3) << 8)
	+ ((((WebRtc_UWord16) pw16_data[1]) & 0xFF00) >> 8);
	}
	#endif

	if (i_MaximumPayloads < 2 \|\| singlePayload == 1)
	{
	/* Reject the redundancy; or no redundant payload present. */
	for (i_k = 1; i_k < i_MaximumPayloads; i_k++)
	{
	RTPheader[i_k]->payloadType = -1;
	RTPheader[i_k]->payloadLen = 0;
	}

	/* update the pointer for the main data */
	pw16_data = &pw16_data[(5 + i_blockLength) >> 1];
	RTPheader[0]->starts_byte1 = (5 + i_blockLength) & 0x1;
	RTPheader[0]->payloadLen = RTPheader[0]->payloadLen - (i_blockLength + 5)
	- i_discardedBlockLength;
	RTPheader[0]->payload = pw16_data;

	*i_No_Of_Payloads = 1;

	}
	else
	{
	/* Redundancy accepted, put the redundancy in second RTPheader. */
	RTPheader[1]->payloadType = uw16_secondPayload;
	RTPheader[1]->payload = &pw16_data[5 >> 1];
	RTPheader[1]->starts_byte1 = 5 & 0x1;
	RTPheader[1]->seqNumber = RTPheader[0]->seqNumber;
	RTPheader[1]->timeStamp = RTPheader[0]->timeStamp - uw16_offsetTimeStamp;
	RTPheader[1]->ssrc = RTPheader[0]->ssrc;
	RTPheader[1]->payloadLen = i_blockLength;

	/* Modify first RTP packet, so that it contains the main data. */
	RTPheader[0]->payload = &pw16_data[(5 + i_blockLength) >> 1];
	RTPheader[0]->starts_byte1 = (5 + i_blockLength) & 0x1;
	RTPheader[0]->payloadLen = RTPheader[0]->payloadLen - (i_blockLength + 5)
	- i_discardedBlockLength;

	/* Clear the following payloads. */
	for (i_k = 2; i_k < i_MaximumPayloads; i_k++)
	{
	RTPheader[i_k]->payloadType = -1;
	RTPheader[i_k]->payloadLen = 0;
	}

	*i_No_Of_Payloads = 2;
	}
	return 0;
	}

	#endif