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ffmpeg / libavformat / rtpdec_h264.c @ 7aa0118c

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/*
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 * RTP H264 Protocol (RFC3984)
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 * Copyright (c) 2006 Ryan Martell
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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/**
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* @file
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 * @brief H.264 / RTP Code (RFC3984)
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 * @author Ryan Martell <rdm4@martellventures.com>
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 *
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 * @note Notes:
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 * Notes:
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 * This currently supports packetization mode:
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 * Single Nal Unit Mode (0), or
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 * Non-Interleaved Mode (1).  It currently does not support
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 * Interleaved Mode (2). (This requires implementing STAP-B, MTAP16, MTAP24, FU-B packet types)
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 *
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 * @note TODO:
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 * 1) RTCP sender reports for udp streams are required..
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 *
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 */
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#include "libavutil/base64.h"
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#include "libavutil/avstring.h"
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#include "libavcodec/get_bits.h"
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#include "avformat.h"
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#include "mpegts.h"
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#include <unistd.h>
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#include "network.h"
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#include <assert.h>
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#include "rtpdec.h"
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#include "rtpdec_h264.h"
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/**
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    RTP/H264 specific private data.
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*/
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struct PayloadContext {
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    unsigned long cookie;       ///< sanity check, to make sure we get the pointer we're expecting.
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    //sdp setup parameters
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    uint8_t profile_idc;        ///< from the sdp setup parameters.
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    uint8_t profile_iop;        ///< from the sdp setup parameters.
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    uint8_t level_idc;          ///< from the sdp setup parameters.
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    int packetization_mode;     ///< from the sdp setup parameters.
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#ifdef DEBUG
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    int packet_types_received[32];
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#endif
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};
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#define MAGIC_COOKIE (0xdeadbeef)       ///< Cookie for the extradata; to verify we are what we think we are, and that we haven't been freed.
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#define DEAD_COOKIE (0xdeaddead)        ///< Cookie for the extradata; once it is freed.
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/* ---------------- private code */
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static int sdp_parse_fmtp_config_h264(AVStream * stream,
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                                       PayloadContext * h264_data,
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                                       char *attr, char *value)
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{
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    AVCodecContext *codec = stream->codec;
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    assert(codec->codec_id == CODEC_ID_H264);
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    assert(h264_data != NULL);
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    if (!strcmp(attr, "packetization-mode")) {
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        av_log(codec, AV_LOG_DEBUG, "RTP Packetization Mode: %d\n", atoi(value));
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        h264_data->packetization_mode = atoi(value);
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        /*
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           Packetization Mode:
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           0 or not present: Single NAL mode (Only nals from 1-23 are allowed)
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           1: Non-interleaved Mode: 1-23, 24 (STAP-A), 28 (FU-A) are allowed.
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           2: Interleaved Mode: 25 (STAP-B), 26 (MTAP16), 27 (MTAP24), 28 (FU-A), and 29 (FU-B) are allowed.
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         */
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        if (h264_data->packetization_mode > 1)
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            av_log(codec, AV_LOG_ERROR,
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                   "Interleaved RTP mode is not supported yet.");
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    } else if (!strcmp(attr, "profile-level-id")) {
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        if (strlen(value) == 6) {
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            char buffer[3];
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            // 6 characters=3 bytes, in hex.
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            uint8_t profile_idc;
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            uint8_t profile_iop;
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            uint8_t level_idc;
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            buffer[0] = value[0]; buffer[1] = value[1]; buffer[2] = '\0';
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            profile_idc = strtol(buffer, NULL, 16);
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            buffer[0] = value[2]; buffer[1] = value[3];
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            profile_iop = strtol(buffer, NULL, 16);
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            buffer[0] = value[4]; buffer[1] = value[5];
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            level_idc = strtol(buffer, NULL, 16);
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            // set the parameters...
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            av_log(codec, AV_LOG_DEBUG,
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                   "RTP Profile IDC: %x Profile IOP: %x Level: %x\n",
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                   profile_idc, profile_iop, level_idc);
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            h264_data->profile_idc = profile_idc;
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            h264_data->profile_iop = profile_iop;
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            h264_data->level_idc = level_idc;
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        }
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    } else  if (!strcmp(attr, "sprop-parameter-sets")) {
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        uint8_t start_sequence[]= { 0, 0, 1 };
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        codec->extradata_size= 0;
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        codec->extradata= NULL;
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        while (*value) {
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            char base64packet[1024];
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            uint8_t decoded_packet[1024];
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            uint32_t packet_size;
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            char *dst = base64packet;
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            while (*value && *value != ','
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                   && (dst - base64packet) < sizeof(base64packet) - 1) {
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                *dst++ = *value++;
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            }
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            *dst++ = '\0';
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            if (*value == ',')
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                value++;
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            packet_size= av_base64_decode(decoded_packet, base64packet, sizeof(decoded_packet));
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            if (packet_size) {
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                uint8_t *dest = av_malloc(packet_size + sizeof(start_sequence) +
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                                         codec->extradata_size +
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                                         FF_INPUT_BUFFER_PADDING_SIZE);
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                if(dest)
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                {
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                    if(codec->extradata_size)
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                    {
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                        // av_realloc?
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                        memcpy(dest, codec->extradata, codec->extradata_size);
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                        av_free(codec->extradata);
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                    }
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                    memcpy(dest+codec->extradata_size, start_sequence, sizeof(start_sequence));
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                    memcpy(dest+codec->extradata_size+sizeof(start_sequence), decoded_packet, packet_size);
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                    memset(dest+codec->extradata_size+sizeof(start_sequence)+
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                           packet_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
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                    codec->extradata= dest;
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                    codec->extradata_size+= sizeof(start_sequence)+packet_size;
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                } else {
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                    av_log(codec, AV_LOG_ERROR, "Unable to allocate memory for extradata!");
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                    return AVERROR(ENOMEM);
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                }
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            }
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        }
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        av_log(codec, AV_LOG_DEBUG, "Extradata set to %p (size: %d)!", codec->extradata, codec->extradata_size);
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    }
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    return 0;
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}
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// return 0 on packet, no more left, 1 on packet, 1 on partial packet...
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static int h264_handle_packet(AVFormatContext *ctx,
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                              PayloadContext *data,
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                              AVStream *st,
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                              AVPacket * pkt,
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                              uint32_t * timestamp,
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                              const uint8_t * buf,
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                              int len, int flags)
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{
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    uint8_t nal = buf[0];
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    uint8_t type = (nal & 0x1f);
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    int result= 0;
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    uint8_t start_sequence[]= {0, 0, 1};
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#ifdef DEBUG
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    assert(data);
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    assert(data->cookie == MAGIC_COOKIE);
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#endif
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    assert(buf);
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    if (type >= 1 && type <= 23)
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        type = 1;              // simplify the case. (these are all the nal types used internally by the h264 codec)
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    switch (type) {
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    case 0:                    // undefined;
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        result= -1;
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        break;
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    case 1:
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        av_new_packet(pkt, len+sizeof(start_sequence));
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        memcpy(pkt->data, start_sequence, sizeof(start_sequence));
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        memcpy(pkt->data+sizeof(start_sequence), buf, len);
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#ifdef DEBUG
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        data->packet_types_received[nal & 0x1f]++;
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#endif
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        break;
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    case 24:                   // STAP-A (one packet, multiple nals)
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        // consume the STAP-A NAL
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        buf++;
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        len--;
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        // first we are going to figure out the total size....
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        {
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            int pass= 0;
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            int total_length= 0;
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            uint8_t *dst= NULL;
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            for(pass= 0; pass<2; pass++) {
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                const uint8_t *src= buf;
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                int src_len= len;
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                do {
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                    uint16_t nal_size = AV_RB16(src); // this going to be a problem if unaligned (can it be?)
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                    // consume the length of the aggregate...
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                    src += 2;
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                    src_len -= 2;
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                    if (nal_size <= src_len) {
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                        if(pass==0) {
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                            // counting...
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                            total_length+= sizeof(start_sequence)+nal_size;
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                        } else {
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                            // copying
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                            assert(dst);
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                            memcpy(dst, start_sequence, sizeof(start_sequence));
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                            dst+= sizeof(start_sequence);
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                            memcpy(dst, src, nal_size);
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#ifdef DEBUG
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                            data->packet_types_received[*src & 0x1f]++;
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#endif
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                            dst+= nal_size;
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                        }
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                    } else {
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                        av_log(ctx, AV_LOG_ERROR,
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                               "nal size exceeds length: %d %d\n", nal_size, src_len);
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                    }
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                    // eat what we handled...
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                    src += nal_size;
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                    src_len -= nal_size;
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                    if (src_len < 0)
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                        av_log(ctx, AV_LOG_ERROR,
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                               "Consumed more bytes than we got! (%d)\n", src_len);
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                } while (src_len > 2);      // because there could be rtp padding..
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                if(pass==0) {
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                    // now we know the total size of the packet (with the start sequences added)
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                    av_new_packet(pkt, total_length);
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                    dst= pkt->data;
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                } else {
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                    assert(dst-pkt->data==total_length);
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                }
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            }
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        }
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        break;
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    case 25:                   // STAP-B
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    case 26:                   // MTAP-16
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    case 27:                   // MTAP-24
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    case 29:                   // FU-B
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        av_log(ctx, AV_LOG_ERROR,
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               "Unhandled type (%d) (See RFC for implementation details\n",
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               type);
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        result= -1;
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        break;
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    case 28:                   // FU-A (fragmented nal)
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        buf++;
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        len--;                  // skip the fu_indicator
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        {
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            // these are the same as above, we just redo them here for clarity...
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            uint8_t fu_indicator = nal;
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            uint8_t fu_header = *buf;   // read the fu_header.
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            uint8_t start_bit = fu_header >> 7;
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//            uint8_t end_bit = (fu_header & 0x40) >> 6;
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            uint8_t nal_type = (fu_header & 0x1f);
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            uint8_t reconstructed_nal;
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            // reconstruct this packet's true nal; only the data follows..
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            reconstructed_nal = fu_indicator & (0xe0);  // the original nal forbidden bit and NRI are stored in this packet's nal;
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            reconstructed_nal |= nal_type;
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            // skip the fu_header...
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            buf++;
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            len--;
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#ifdef DEBUG
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            if (start_bit)
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                data->packet_types_received[nal_type]++;
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#endif
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            if(start_bit) {
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                // copy in the start sequence, and the reconstructed nal....
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                av_new_packet(pkt, sizeof(start_sequence)+sizeof(nal)+len);
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                memcpy(pkt->data, start_sequence, sizeof(start_sequence));
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                pkt->data[sizeof(start_sequence)]= reconstructed_nal;
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                memcpy(pkt->data+sizeof(start_sequence)+sizeof(nal), buf, len);
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            } else {
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                av_new_packet(pkt, len);
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                memcpy(pkt->data, buf, len);
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            }
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        }
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        break;
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    case 30:                   // undefined
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    case 31:                   // undefined
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    default:
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        av_log(ctx, AV_LOG_ERROR, "Undefined type (%d)", type);
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        result= -1;
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        break;
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    }
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    pkt->stream_index = st->index;
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    return result;
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}
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/* ---------------- public code */
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static PayloadContext *h264_new_context(void)
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{
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    PayloadContext *data =
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        av_mallocz(sizeof(PayloadContext) +
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                   FF_INPUT_BUFFER_PADDING_SIZE);
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    if (data) {
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        data->cookie = MAGIC_COOKIE;
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    }
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    return data;
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}
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static void h264_free_context(PayloadContext *data)
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{
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#ifdef DEBUG
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    int ii;
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    for (ii = 0; ii < 32; ii++) {
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        if (data->packet_types_received[ii])
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            av_log(NULL, AV_LOG_DEBUG, "Received %d packets of type %d\n",
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                   data->packet_types_received[ii], ii);
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    }
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#endif
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    assert(data);
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    assert(data->cookie == MAGIC_COOKIE);
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    // avoid stale pointers (assert)
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    data->cookie = DEAD_COOKIE;
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    // and clear out this...
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    av_free(data);
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}
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static int parse_h264_sdp_line(AVFormatContext *s, int st_index,
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                               PayloadContext *h264_data, const char *line)
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{
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    AVStream *stream = s->streams[st_index];
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    AVCodecContext *codec = stream->codec;
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    const char *p = line;
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    assert(h264_data->cookie == MAGIC_COOKIE);
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    if (av_strstart(p, "framesize:", &p)) {
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        char buf1[50];
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        char *dst = buf1;
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        // remove the protocol identifier..
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        while (*p && *p == ' ') p++; // strip spaces.
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        while (*p && *p != ' ') p++; // eat protocol identifier
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        while (*p && *p == ' ') p++; // strip trailing spaces.
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        while (*p && *p != '-' && (dst - buf1) < sizeof(buf1) - 1) {
378
            *dst++ = *p++;
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        }
380
        *dst = '\0';
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        // a='framesize:96 320-240'
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        // set our parameters..
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        codec->width = atoi(buf1);
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        codec->height = atoi(p + 1); // skip the -
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        codec->pix_fmt = PIX_FMT_YUV420P;
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    } else if (av_strstart(p, "fmtp:", &p)) {
388
        char attr[256];
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        char value[4096];
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        // remove the protocol identifier..
392
        while (*p && *p == ' ') p++; // strip spaces.
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        while (*p && *p != ' ') p++; // eat protocol identifier
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        while (*p && *p == ' ') p++; // strip trailing spaces.
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        /* loop on each attribute */
397
        while (ff_rtsp_next_attr_and_value
398
               (&p, attr, sizeof(attr), value, sizeof(value))) {
399
            /* grab the codec extra_data from the config parameter of the fmtp line */
400
            sdp_parse_fmtp_config_h264(stream, h264_data, attr, value);
401
        }
402
    } else if (av_strstart(p, "cliprect:", &p)) {
403
        // could use this if we wanted.
404
    }
405

    
406
    return 0;                   // keep processing it the normal way...
407
}
408

    
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/**
410
This is the structure for expanding on the dynamic rtp protocols (makes everything static. yay!)
411
*/
412
RTPDynamicProtocolHandler ff_h264_dynamic_handler = {
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    .enc_name         = "H264",
414
    .codec_type       = AVMEDIA_TYPE_VIDEO,
415
    .codec_id         = CODEC_ID_H264,
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    .parse_sdp_a_line = parse_h264_sdp_line,
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    .open             = h264_new_context,
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    .close            = h264_free_context,
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    .parse_packet     = h264_handle_packet
420
};