/*

 * RTP H.264 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)

 */

#include "libavutil/attributes.h"

#include "libavutil/base64.h"

#include "libavutil/intreadwrite.h"

#include "libavutil/avstring.h"

#include "libavutil/mem.h"

#include "avformat.h"

#include "rtpdec.h"

#include "rtpdec_formats.h"

struct PayloadContext {

    // sdp setup parameters

    uint8_t profile_idc;

    uint8_t profile_iop;

    uint8_t level_idc;

    int packetization_mode;

#ifdef DEBUG

    int packet_types_received[32];

#endif

};

#ifdef DEBUG

#define COUNT_NAL_TYPE(data, nal) data->packet_types_received[(nal) & 0x1f]++

#define NAL_COUNTERS data->packet_types_received

#else

#define COUNT_NAL_TYPE(data, nal) do { } while (0)

#define NAL_COUNTERS NULL

#endif

#define NAL_MASK 0x1f

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

static void parse_profile_level_id(AVFormatContext *s,

                                   PayloadContext *h264_data,

                                   const char *value)

{

    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);

    av_log(s, 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;

}

int ff_h264_parse_sprop_parameter_sets(AVFormatContext *s,

                                       uint8_t **data_ptr, int *size_ptr,

                                       const char *value)

{

    char base64packet[1024];

    uint8_t decoded_packet[1024];

    int packet_size;

    while (*value) {

        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 > 0) {

            uint8_t *dest = av_realloc(*data_ptr,

                                       packet_size + sizeof(start_sequence) +

                                       *size_ptr +

                                       AV_INPUT_BUFFER_PADDING_SIZE);

            if (!dest) {

                av_log(s, AV_LOG_ERROR,

                       "Unable to allocate memory for extradata!\n");

                return AVERROR(ENOMEM);

            }

            *data_ptr = dest;

            memcpy(dest + *size_ptr, start_sequence,

                   sizeof(start_sequence));

            memcpy(dest + *size_ptr + sizeof(start_sequence),

                   decoded_packet, packet_size);

            memset(dest + *size_ptr + sizeof(start_sequence) +

                   packet_size, 0, AV_INPUT_BUFFER_PADDING_SIZE);

            *size_ptr += sizeof(start_sequence) + packet_size;

        }

    }

    return 0;

}

static int sdp_parse_fmtp_config_h264(AVFormatContext *s,

                                      AVStream *stream,

                                      PayloadContext *h264_data,

                                      const char *attr, const char *value)

{

    AVCodecParameters *par = stream->codecpar;

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

        av_log(s, 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(s, AV_LOG_ERROR,

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

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

        if (strlen(value) == 6)

            parse_profile_level_id(s, h264_data, value);

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

        int ret;

        if (*value == 0 || value[strlen(value) - 1] == ',') {

            av_log(s, AV_LOG_WARNING, "Missing PPS in sprop-parameter-sets, ignoring\n");

            return 0;

        }

        par->extradata_size = 0;

        av_freep(&par->extradata);

        ret = ff_h264_parse_sprop_parameter_sets(s, &par->extradata,

                                                 &par->extradata_size, value);

        av_log(s, AV_LOG_DEBUG, "Extradata set to %p (size: %d)\n",

               par->extradata, par->extradata_size);

        return ret;

    }

    return 0;

}

void ff_h264_parse_framesize(AVCodecParameters *par, const char *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

    par->width   = atoi(buf1);

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

}

int ff_h264_handle_aggregated_packet(AVFormatContext *ctx, PayloadContext *data, AVPacket *pkt,

                                     const uint8_t *buf, int len,

                                     int skip_between, int *nal_counters,

                                     int nal_mask)

{

    int pass         = 0;

    int total_length = 0;

    uint8_t *dst     = NULL;

    int ret;

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

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

        const uint8_t *src = buf;

        int src_len        = len;

        while (src_len > 2) {

            uint16_t nal_size = AV_RB16(src);

            // 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

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

                    dst += sizeof(start_sequence);

                    memcpy(dst, src, nal_size);

                    if (nal_counters)

                        nal_counters[(*src) & nal_mask]++;

                    dst += nal_size;

                }

            } else {

                av_log(ctx, AV_LOG_ERROR,

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

                return AVERROR_INVALIDDATA;

            }

            // eat what we handled

            src     += nal_size + skip_between;

            src_len -= nal_size + skip_between;

        }

        if (pass == 0) {

            /* now we know the total size of the packet (with the

             * start sequences added) */

            if ((ret = av_new_packet(pkt, total_length)) < 0)

                return ret;

            dst = pkt->data;

        }

    }

    return 0;

}

int ff_h264_handle_frag_packet(AVPacket *pkt, const uint8_t *buf, int len,

                               int start_bit, const uint8_t *nal_header,

                               int nal_header_len)

{

    int ret;

    int tot_len = len;

    int pos = 0;

    if (start_bit)

        tot_len += sizeof(start_sequence) + nal_header_len;

    if ((ret = av_new_packet(pkt, tot_len)) < 0)

        return ret;

    if (start_bit) {

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

        pos += sizeof(start_sequence);

        memcpy(pkt->data + pos, nal_header, nal_header_len);

        pos += nal_header_len;

    }

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

    return 0;

}

static int h264_handle_packet_fu_a(AVFormatContext *ctx, PayloadContext *data, AVPacket *pkt,

                                   const uint8_t *buf, int len,

                                   int *nal_counters, int nal_mask)

{

    uint8_t fu_indicator, fu_header, start_bit, nal_type, nal;

    if (len < 3) {

        av_log(ctx, AV_LOG_ERROR, "Too short data for FU-A H.264 RTP packet\n");

        return AVERROR_INVALIDDATA;

    }

    fu_indicator = buf[0];

    fu_header    = buf[1];

    start_bit    = fu_header >> 7;

    nal_type     = fu_header & 0x1f;

    nal          = fu_indicator & 0xe0 | nal_type;

    // skip the fu_indicator and fu_header

    buf += 2;

    len -= 2;

    if (start_bit && nal_counters)

        nal_counters[nal_type & nal_mask]++;

    return ff_h264_handle_frag_packet(pkt, buf, len, start_bit, &nal, 1);

}

// 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, uint16_t seq,

                              int flags)

{

    uint8_t nal;

    uint8_t type;

    int result = 0;

    if (!len) {

        av_log(ctx, AV_LOG_ERROR, "Empty H.264 RTP packet\n");

        return AVERROR_INVALIDDATA;

    }

    nal  = buf[0];

    type = nal & 0x1f;

    /* Simplify the case (these are all the NAL types used internally by

     * the H.264 codec). */

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

        type = 1;

    switch (type) {

    case 0:                    // undefined, but pass them through

    case 1:

        if ((result = av_new_packet(pkt, len + sizeof(start_sequence))) < 0)

            return result;

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

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

        COUNT_NAL_TYPE(data, nal);

        break;

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

        // consume the STAP-A NAL

        buf++;

        len--;

        result = ff_h264_handle_aggregated_packet(ctx, data, pkt, buf, len, 0,

                                                  NAL_COUNTERS, NAL_MASK);

        break;

    case 25:                   // STAP-B

    case 26:                   // MTAP-16

    case 27:                   // MTAP-24

    case 29:                   // FU-B

        avpriv_report_missing_feature(ctx, "RTP H.264 NAL unit type %d", type);

        result = AVERROR_PATCHWELCOME;

        break;

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

        result = h264_handle_packet_fu_a(ctx, data, pkt, buf, len,

                                         NAL_COUNTERS, NAL_MASK);

        break;

    case 30:                   // undefined

    case 31:                   // undefined

    default:

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

        result = AVERROR_INVALIDDATA;

        break;

    }

    pkt->stream_index = st->index;

    return result;

}

static void h264_close_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

}

static int parse_h264_sdp_line(AVFormatContext *s, int st_index,

                               PayloadContext *h264_data, const char *line)

{

    AVStream *stream;

    const char *p = line;

    if (st_index < 0)

        return 0;

    stream = s->streams[st_index];

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

        ff_h264_parse_framesize(stream->codecpar, p);

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

        return ff_parse_fmtp(s, stream, h264_data, p, sdp_parse_fmtp_config_h264);

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

        // could use this if we wanted.

    }

    return 0;

}

const RTPDynamicProtocolHandler ff_h264_dynamic_handler = {

    .enc_name         = "H264",

    .codec_type       = AVMEDIA_TYPE_VIDEO,

    .codec_id         = AV_CODEC_ID_H264,

    .need_parsing     = AVSTREAM_PARSE_FULL,

    .priv_data_size   = sizeof(PayloadContext),

    .parse_sdp_a_line = parse_h264_sdp_line,

    .close            = h264_close_context,

    .parse_packet     = h264_handle_packet,

};