PeerStreamer

/*

 * RTP H264 Protocol (RFC3984)

 * Copyright (c) 2006 Ryan Martell

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/**

* @file

 * @brief H.264 / RTP Code (RFC3984)

 * @author Ryan Martell <rdm4@martellventures.com>

 *

 * @note Notes:

 * Notes:

 * This currently supports packetization mode:

 * Single Nal Unit Mode (0), or

 * Non-Interleaved Mode (1).  It currently does not support

 * Interleaved Mode (2). (This requires implementing STAP-B, MTAP16, MTAP24, FU-B packet types)

 *

 * @note TODO:

 * 1) RTCP sender reports for udp streams are required..

 *

 */

#include "libavutil/base64.h"

#include "libavutil/avstring.h"

#include "libavcodec/get_bits.h"

#include "avformat.h"

#include "mpegts.h"

#include <unistd.h>

#include "network.h"

#include <assert.h>

#include "rtpdec.h"

#include "rtpdec_h264.h"

/**

    RTP/H264 specific private data.

*/

struct PayloadContext {

    unsigned long cookie;       ///< sanity check, to make sure we get the pointer we're expecting.

    //sdp setup parameters

    uint8_t profile_idc;        ///< from the sdp setup parameters.

    uint8_t profile_iop;        ///< from the sdp setup parameters.

    uint8_t level_idc;          ///< from the sdp setup parameters.

    int packetization_mode;     ///< from the sdp setup parameters.

#ifdef DEBUG

    int packet_types_received[32];

#endif

};

#define MAGIC_COOKIE (0xdeadbeef)       ///< Cookie for the extradata; to verify we are what we think we are, and that we haven't been freed.

#define DEAD_COOKIE (0xdeaddead)        ///< Cookie for the extradata; once it is freed.

/* ---------------- private code */

static int sdp_parse_fmtp_config_h264(AVStream * stream,

                                       PayloadContext * h264_data,

                                       char *attr, char *value)

{

    AVCodecContext *codec = stream->codec;

    assert(codec->codec_id == CODEC_ID_H264);

    assert(h264_data != NULL);

    if (!strcmp(attr, "packetization-mode")) {

        av_log(codec, AV_LOG_DEBUG, "RTP Packetization Mode: %d\n", atoi(value));

        h264_data->packetization_mode = atoi(value);

        /*

           Packetization Mode:

           0 or not present: Single NAL mode (Only nals from 1-23 are allowed)

           1: Non-interleaved Mode: 1-23, 24 (STAP-A), 28 (FU-A) are allowed.

           2: Interleaved Mode: 25 (STAP-B), 26 (MTAP16), 27 (MTAP24), 28 (FU-A), and 29 (FU-B) are allowed.

         */

        if (h264_data->packetization_mode > 1)

            av_log(codec, AV_LOG_ERROR,

                   "Interleaved RTP mode is not supported yet.");

    } else if (!strcmp(attr, "profile-level-id")) {

        if (strlen(value) == 6) {

            char buffer[3];

            // 6 characters=3 bytes, in hex.

            uint8_t profile_idc;

            uint8_t profile_iop;

            uint8_t level_idc;

            buffer[0] = value[0]; buffer[1] = value[1]; buffer[2] = '\0';

            profile_idc = strtol(buffer, NULL, 16);

            buffer[0] = value[2]; buffer[1] = value[3];

            profile_iop = strtol(buffer, NULL, 16);

            buffer[0] = value[4]; buffer[1] = value[5];

            level_idc = strtol(buffer, NULL, 16);

            // set the parameters...

            av_log(codec, AV_LOG_DEBUG,

                   "RTP Profile IDC: %x Profile IOP: %x Level: %x\n",

                   profile_idc, profile_iop, level_idc);

            h264_data->profile_idc = profile_idc;

            h264_data->profile_iop = profile_iop;

            h264_data->level_idc = level_idc;

        }

    } else  if (!strcmp(attr, "sprop-parameter-sets")) {

        uint8_t start_sequence[]= { 0, 0, 1 };

        codec->extradata_size= 0;

        codec->extradata= NULL;

        while (*value) {

            char base64packet[1024];

            uint8_t decoded_packet[1024];

            uint32_t packet_size;

            char *dst = base64packet;

            while (*value && *value != ','

                   && (dst - base64packet) < sizeof(base64packet) - 1) {

                *dst++ = *value++;

            }

            *dst++ = '\0';

            if (*value == ',')

                value++;

            packet_size= av_base64_decode(decoded_packet, base64packet, sizeof(decoded_packet));

            if (packet_size) {

                uint8_t *dest = av_malloc(packet_size + sizeof(start_sequence) +

                                         codec->extradata_size +

                                         FF_INPUT_BUFFER_PADDING_SIZE);

                if(dest)

                {

                    if(codec->extradata_size)

                    {

                        // av_realloc?

                        memcpy(dest, codec->extradata, codec->extradata_size);

                        av_free(codec->extradata);

                    }

                    memcpy(dest+codec->extradata_size, start_sequence, sizeof(start_sequence));

                    memcpy(dest+codec->extradata_size+sizeof(start_sequence), decoded_packet, packet_size);

                    memset(dest+codec->extradata_size+sizeof(start_sequence)+

                           packet_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);

                    codec->extradata= dest;

                    codec->extradata_size+= sizeof(start_sequence)+packet_size;

                } else {

                    av_log(codec, AV_LOG_ERROR, "Unable to allocate memory for extradata!");

                    return AVERROR(ENOMEM);

                }

            }

        }

        av_log(codec, AV_LOG_DEBUG, "Extradata set to %p (size: %d)!", codec->extradata, codec->extradata_size);

    }

    return 0;

}

// return 0 on packet, no more left, 1 on packet, 1 on partial packet...

static int h264_handle_packet(AVFormatContext *ctx,

                              PayloadContext *data,

                              AVStream *st,

                              AVPacket * pkt,

                              uint32_t * timestamp,

                              const uint8_t * buf,

                              int len, int flags)

{

    uint8_t nal = buf[0];

    uint8_t type = (nal & 0x1f);

    int result= 0;

    uint8_t start_sequence[]= {0, 0, 1};

#ifdef DEBUG

    assert(data);

    assert(data->cookie == MAGIC_COOKIE);

#endif

    assert(buf);

    if (type >= 1 && type <= 23)

        type = 1;              // simplify the case. (these are all the nal types used internally by the h264 codec)

    switch (type) {

    case 0:                    // undefined;

        result= -1;

        break;

    case 1:

        av_new_packet(pkt, len+sizeof(start_sequence));

        memcpy(pkt->data, start_sequence, sizeof(start_sequence));

        memcpy(pkt->data+sizeof(start_sequence), buf, len);

#ifdef DEBUG

        data->packet_types_received[nal & 0x1f]++;

#endif

        break;

    case 24:                   // STAP-A (one packet, multiple nals)

        // consume the STAP-A NAL

        buf++;

        len--;

        // first we are going to figure out the total size....

        {

            int pass= 0;

            int total_length= 0;

            uint8_t *dst= NULL;

            for(pass= 0; pass<2; pass++) {

                const uint8_t *src= buf;

                int src_len= len;

                do {

                    uint16_t nal_size = AV_RB16(src); // this going to be a problem if unaligned (can it be?)

                    // consume the length of the aggregate...

                    src += 2;

                    src_len -= 2;

                    if (nal_size <= src_len) {

                        if(pass==0) {

                            // counting...

                            total_length+= sizeof(start_sequence)+nal_size;

                        } else {

                            // copying

                            assert(dst);

                            memcpy(dst, start_sequence, sizeof(start_sequence));

                            dst+= sizeof(start_sequence);

                            memcpy(dst, src, nal_size);

#ifdef DEBUG

                            data->packet_types_received[*src & 0x1f]++;

#endif

                            dst+= nal_size;

                        }

                    } else {

                        av_log(ctx, AV_LOG_ERROR,

                               "nal size exceeds length: %d %d\n", nal_size, src_len);

                    }

                    // eat what we handled...

                    src += nal_size;

                    src_len -= nal_size;

                    if (src_len < 0)

                        av_log(ctx, AV_LOG_ERROR,

                               "Consumed more bytes than we got! (%d)\n", src_len);

                } while (src_len > 2);      // because there could be rtp padding..

                if(pass==0) {

                    // now we know the total size of the packet (with the start sequences added)

                    av_new_packet(pkt, total_length);

                    dst= pkt->data;

                } else {

                    assert(dst-pkt->data==total_length);

                }

            }

        }

        break;

    case 25:                   // STAP-B

    case 26:                   // MTAP-16

    case 27:                   // MTAP-24

    case 29:                   // FU-B

        av_log(ctx, AV_LOG_ERROR,

               "Unhandled type (%d) (See RFC for implementation details\n",

               type);

        result= -1;

        break;

    case 28:                   // FU-A (fragmented nal)

        buf++;

        len--;                  // skip the fu_indicator

        {

            // these are the same as above, we just redo them here for clarity...

            uint8_t fu_indicator = nal;

            uint8_t fu_header = *buf;   // read the fu_header.

            uint8_t start_bit = fu_header >> 7;

//            uint8_t end_bit = (fu_header & 0x40) >> 6;

            uint8_t nal_type = (fu_header & 0x1f);

            uint8_t reconstructed_nal;

            // reconstruct this packet's true nal; only the data follows..

            reconstructed_nal = fu_indicator & (0xe0);  // the original nal forbidden bit and NRI are stored in this packet's nal;

            reconstructed_nal |= nal_type;

            // skip the fu_header...

            buf++;

            len--;

#ifdef DEBUG

            if (start_bit)

                data->packet_types_received[nal_type]++;

#endif

            if(start_bit) {

                // copy in the start sequence, and the reconstructed nal....

                av_new_packet(pkt, sizeof(start_sequence)+sizeof(nal)+len);

                memcpy(pkt->data, start_sequence, sizeof(start_sequence));

                pkt->data[sizeof(start_sequence)]= reconstructed_nal;

                memcpy(pkt->data+sizeof(start_sequence)+sizeof(nal), buf, len);

            } else {

                av_new_packet(pkt, len);

                memcpy(pkt->data, buf, len);

            }

        }

        break;

    case 30:                   // undefined

    case 31:                   // undefined

    default:

        av_log(ctx, AV_LOG_ERROR, "Undefined type (%d)", type);

        result= -1;

        break;

    }

    pkt->stream_index = st->index;

    return result;

}

/* ---------------- public code */

static PayloadContext *h264_new_context(void)

{

    PayloadContext *data =

        av_mallocz(sizeof(PayloadContext) +

                   FF_INPUT_BUFFER_PADDING_SIZE);

    if (data) {

        data->cookie = MAGIC_COOKIE;

    }

    return data;

}

static void h264_free_context(PayloadContext *data)

{

#ifdef DEBUG

    int ii;

    for (ii = 0; ii < 32; ii++) {

        if (data->packet_types_received[ii])

            av_log(NULL, AV_LOG_DEBUG, "Received %d packets of type %d\n",

                   data->packet_types_received[ii], ii);

    }

#endif

    assert(data);

    assert(data->cookie == MAGIC_COOKIE);

    // avoid stale pointers (assert)

    data->cookie = DEAD_COOKIE;

    // and clear out this...

    av_free(data);

}

static int parse_h264_sdp_line(AVFormatContext *s, int st_index,

                               PayloadContext *h264_data, const char *line)

{

    AVStream *stream = s->streams[st_index];

    AVCodecContext *codec = stream->codec;

    const char *p = line;

    assert(h264_data->cookie == MAGIC_COOKIE);

    if (av_strstart(p, "framesize:", &p)) {

        char buf1[50];

        char *dst = buf1;

        // remove the protocol identifier..

        while (*p && *p == ' ') p++; // strip spaces.

        while (*p && *p != ' ') p++; // eat protocol identifier

        while (*p && *p == ' ') p++; // strip trailing spaces.

        while (*p && *p != '-' && (dst - buf1) < sizeof(buf1) - 1) {

            *dst++ = *p++;

        }

        *dst = '\0';

        // a='framesize:96 320-240'

        // set our parameters..

        codec->width = atoi(buf1);

        codec->height = atoi(p + 1); // skip the -

        codec->pix_fmt = PIX_FMT_YUV420P;

    } else if (av_strstart(p, "fmtp:", &p)) {

        char attr[256];

        char value[4096];

        // remove the protocol identifier..

        while (*p && *p == ' ') p++; // strip spaces.

        while (*p && *p != ' ') p++; // eat protocol identifier

        while (*p && *p == ' ') p++; // strip trailing spaces.

        /* loop on each attribute */

        while (ff_rtsp_next_attr_and_value

               (&p, attr, sizeof(attr), value, sizeof(value))) {

            /* grab the codec extra_data from the config parameter of the fmtp line */

            sdp_parse_fmtp_config_h264(stream, h264_data, attr, value);

        }

    } else if (av_strstart(p, "cliprect:", &p)) {

        // could use this if we wanted.

    }

    return 0;                   // keep processing it the normal way...

}

/**

This is the structure for expanding on the dynamic rtp protocols (makes everything static. yay!)

*/

RTPDynamicProtocolHandler ff_h264_dynamic_handler = {

    .enc_name         = "H264",

    .codec_type       = AVMEDIA_TYPE_VIDEO,

    .codec_id         = CODEC_ID_H264,

    .parse_sdp_a_line = parse_h264_sdp_line,

    .open             = h264_new_context,

    .close            = h264_free_context,

    .parse_packet     = h264_handle_packet

};