137 lines
3.9 KiB
C++
137 lines
3.9 KiB
C++
/// RFC3016 RTP Payload Format for MPEG-4 Audio/Visual Streams
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/// RFC6416 RTP Payload Format for MPEG-4 Audio/Visual Streams
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///
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/// MPEG-4 Audio streams MUST be formatted LATM (Lowoverhead
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/// MPEG-4 Audio Transport Multiplex)[14496 - 3] streams, and the
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/// LATM-based streams are then mapped onto RTP packets
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#include "rtp-packet.h"
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#include "rtp-profile.h"
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#include "rtp-payload-internal.h"
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#include <stdlib.h>
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#include <string.h>
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#include <assert.h>
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#include <errno.h>
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struct rtp_encode_mp4a_latm_t
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{
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struct rtp_packet_t pkt;
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struct rtp_payload_t handler;
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void* cbparam;
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int size;
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};
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static void* rtp_mp4a_latm_pack_create(int size, uint8_t pt, uint16_t seq, uint32_t ssrc, struct rtp_payload_t *handler, void* cbparam)
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{
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struct rtp_encode_mp4a_latm_t *packer;
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packer = (struct rtp_encode_mp4a_latm_t *)calloc(1, sizeof(*packer));
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if (!packer) return NULL;
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memcpy(&packer->handler, handler, sizeof(packer->handler));
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packer->cbparam = cbparam;
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packer->size = size;
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packer->pkt.rtp.v = RTP_VERSION;
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packer->pkt.rtp.pt = pt;
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packer->pkt.rtp.seq = seq;
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packer->pkt.rtp.ssrc = ssrc;
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return packer;
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}
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static void rtp_mp4a_latm_pack_destroy(void* pack)
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{
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struct rtp_encode_mp4a_latm_t *packer;
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packer = (struct rtp_encode_mp4a_latm_t *)pack;
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#if defined(_DEBUG) || defined(DEBUG)
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memset(packer, 0xCC, sizeof(*packer));
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#endif
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free(packer);
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}
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static void rtp_mp4a_latm_pack_get_info(void* pack, uint16_t* seq, uint32_t* timestamp)
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{
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struct rtp_encode_mp4a_latm_t *packer;
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packer = (struct rtp_encode_mp4a_latm_t *)pack;
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*seq = (uint16_t)packer->pkt.rtp.seq;
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*timestamp = packer->pkt.rtp.timestamp;
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}
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static int rtp_mp4a_latm_pack_input(void* pack, const void* data, int bytes, uint32_t timestamp)
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{
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int r;
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int n, len;
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uint8_t *rtp;
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uint8_t hd[40]; // 10KB
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const uint8_t *ptr;
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struct rtp_encode_mp4a_latm_t *packer;
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packer = (struct rtp_encode_mp4a_latm_t *)pack;
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assert(packer->pkt.rtp.timestamp != timestamp || !packer->pkt.payload /*first packet*/);
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packer->pkt.rtp.timestamp = timestamp; //(uint32_t)(time * KHz); // ms -> 90KHZ (RFC2250 section2 p2)
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r = 0;
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ptr = (const uint8_t *)data;
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#if defined(RTP_MP4A_LATM_SKIP_ADTS)
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if (0xFF == ptr[0] && 0xF0 == (ptr[1] & 0xF0) && bytes > 7)
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{
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// skip ADTS header
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assert(bytes == (((ptr[3] & 0x03) << 11) | (ptr[4] << 3) | ((ptr[5] >> 5) & 0x07)));
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ptr += 7;
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bytes -= 7;
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}
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#endif
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// ISO/IEC 14496-3:200X(E)
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// Table 1.44 - Syntax of PayloadLengthInfo() (p84)
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len = bytes / 255 + 1;
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if (len > sizeof(hd))
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{
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assert(0);
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return -E2BIG; // invalid packet
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}
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memset(hd, 255, len - 1);
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hd[len - 1] = bytes % 255;
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for (; 0 == r && bytes > 0; ++packer->pkt.rtp.seq)
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{
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packer->pkt.payload = ptr;
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packer->pkt.payloadlen = (bytes + len + RTP_FIXED_HEADER) <= packer->size ? bytes : (packer->size - len - RTP_FIXED_HEADER);
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ptr += packer->pkt.payloadlen;
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bytes -= packer->pkt.payloadlen;
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n = RTP_FIXED_HEADER + len + packer->pkt.payloadlen;
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rtp = (uint8_t*)packer->handler.alloc(packer->cbparam, n);
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if (!rtp) return -ENOMEM;
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// Marker (M) bit: The marker bit indicates audioMuxElement boundaries.
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// It is set to 1 to indicate that the RTP packet contains a complete
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// audioMuxElement or the last fragment of an audioMuxElement.
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packer->pkt.rtp.m = (0 == bytes) ? 1 : 0;
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n = rtp_packet_serialize_header(&packer->pkt, rtp, n);
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if (n != RTP_FIXED_HEADER)
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{
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assert(0);
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return -1;
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}
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if (len > 0) memcpy(rtp + n, hd, len);
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memcpy(rtp + n + len, packer->pkt.payload, packer->pkt.payloadlen);
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r = packer->handler.packet(packer->cbparam, rtp, n + len + packer->pkt.payloadlen, packer->pkt.rtp.timestamp, 0);
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packer->handler.free(packer->cbparam, rtp);
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len = 0; // write PayloadLengthInfo once only
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}
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return r;
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}
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struct rtp_payload_encode_t *rtp_mp4a_latm_encode()
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{
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static struct rtp_payload_encode_t encode = {
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rtp_mp4a_latm_pack_create,
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rtp_mp4a_latm_pack_destroy,
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rtp_mp4a_latm_pack_get_info,
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rtp_mp4a_latm_pack_input,
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};
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return &encode;
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}
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