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/*

 * RTP parser for HEVC/H.265 payload format (draft version 6)

 * Copyright (c) 2014 Thomas Volkert 

 *

 * 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

 *

 */

#include "libavutil/avassert.h"

#include "libavutil/avstring.h"

#include "libavutil/base64.h"

#include "libavcodec/get_bits.h"

#include "avformat.h"

#include "rtpdec.h"

#include "rtpdec_formats.h"

#define RTP_HEVC_PAYLOAD_HEADER_SIZE       2

#define RTP_HEVC_FU_HEADER_SIZE            1

#define RTP_HEVC_DONL_FIELD_SIZE           2

#define RTP_HEVC_DOND_FIELD_SIZE           1

#define RTP_HEVC_AP_NALU_LENGTH_FIELD_SIZE 2

#define HEVC_SPECIFIED_NAL_UNIT_TYPES      48

/* SDP out-of-band signaling data */

struct PayloadContext {

    int using_donl_field;

    int profile_id;

    uint8_t *sps, *pps, *vps, *sei;

    int sps_size, pps_size, vps_size, sei_size;

};

static const uint8_t start_sequence[] = { 0x00, 0x00, 0x00, 0x01 };

static av_cold int hevc_sdp_parse_fmtp_config(AVFormatContext *s,

                                              AVStream *stream,

                                              PayloadContext *hevc_data,

                                              const char *attr, const char *value)

{

    /* profile-space: 0-3 */

    /* profile-id: 0-31 */

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

        hevc_data->profile_id = atoi(value);

        av_log(s, AV_LOG_TRACE, "SDP: found profile-id: %d\n", hevc_data->profile_id);

    }

    /* tier-flag: 0-1 */

    /* level-id: 0-255 */

    /* interop-constraints: [base16] */

    /* profile-compatibility-indicator: [base16] */

    /* sprop-sub-layer-id: 0-6, defines highest possible value for TID, default: 6 */

    /* recv-sub-layer-id: 0-6 */

    /* max-recv-level-id: 0-255 */

    /* tx-mode: MSM,SSM */

    /* sprop-vps: [base64] */

    /* sprop-sps: [base64] */

    /* sprop-pps: [base64] */

    /* sprop-sei: [base64] */

    if (!strcmp(attr, "sprop-vps") || !strcmp(attr, "sprop-sps") ||

        !strcmp(attr, "sprop-pps") || !strcmp(attr, "sprop-sei")) {

        uint8_t **data_ptr = NULL;

        int *size_ptr = NULL;

        if (!strcmp(attr, "sprop-vps")) {

            data_ptr = &hevc_data->vps;

            size_ptr = &hevc_data->vps_size;

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

            data_ptr = &hevc_data->sps;

            size_ptr = &hevc_data->sps_size;

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

            data_ptr = &hevc_data->pps;

            size_ptr = &hevc_data->pps_size;

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

            data_ptr = &hevc_data->sei;

            size_ptr = &hevc_data->sei_size;

        } else

            av_assert0(0);

        ff_h264_parse_sprop_parameter_sets(s, data_ptr,

                                           size_ptr, value);

    }

    /* max-lsr, max-lps, max-cpb, max-dpb, max-br, max-tr, max-tc */

    /* max-fps */

    /* sprop-max-don-diff: 0-32767

         When the RTP stream depends on one or more other RTP

         streams (in this case tx-mode MUST be equal to "MSM" and

         MSM is in use), this parameter MUST be present and the

         value MUST be greater than 0.

    */

    if (!strcmp(attr, "sprop-max-don-diff")) {

        if (atoi(value) > 0)

            hevc_data->using_donl_field = 1;

        av_log(s, AV_LOG_TRACE, "Found sprop-max-don-diff in SDP, DON field usage is: %d\n",

                hevc_data->using_donl_field);

    }

    /* sprop-depack-buf-nalus: 0-32767 */

    if (!strcmp(attr, "sprop-depack-buf-nalus")) {

        if (atoi(value) > 0)

            hevc_data->using_donl_field = 1;

        av_log(s, AV_LOG_TRACE, "Found sprop-depack-buf-nalus in SDP, DON field usage is: %d\n",

                hevc_data->using_donl_field);

    }

    /* sprop-depack-buf-bytes: 0-4294967295 */

    /* depack-buf-cap */

    /* sprop-segmentation-id: 0-3 */

    /* sprop-spatial-segmentation-idc: [base16] */

    /* dec-parallel-ca: */

    /* include-dph */

    return 0;

}

static av_cold int hevc_parse_sdp_line(AVFormatContext *ctx, int st_index,

                                       PayloadContext *hevc_data, const char *line)

{

    AVStream *current_stream;

    AVCodecContext *codec;

    const char *sdp_line_ptr = line;

    if (st_index < 0)

        return 0;

    current_stream = ctx->streams[st_index];

    codec  = current_stream->codec;

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

        ff_h264_parse_framesize(codec, sdp_line_ptr);

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

        int ret = ff_parse_fmtp(ctx, current_stream, hevc_data, sdp_line_ptr,

                                hevc_sdp_parse_fmtp_config);

        if (hevc_data->vps_size || hevc_data->sps_size ||

            hevc_data->pps_size || hevc_data->sei_size) {

            av_freep(&codec->extradata);

            codec->extradata_size = hevc_data->vps_size + hevc_data->sps_size +

                                    hevc_data->pps_size + hevc_data->sei_size;

            codec->extradata = av_malloc(codec->extradata_size +

                                         AV_INPUT_BUFFER_PADDING_SIZE);

            if (!codec->extradata) {

                ret = AVERROR(ENOMEM);

                codec->extradata_size = 0;

            } else {

                int pos = 0;

                memcpy(codec->extradata + pos, hevc_data->vps, hevc_data->vps_size);

                pos += hevc_data->vps_size;

                memcpy(codec->extradata + pos, hevc_data->sps, hevc_data->sps_size);

                pos += hevc_data->sps_size;

                memcpy(codec->extradata + pos, hevc_data->pps, hevc_data->pps_size);

                pos += hevc_data->pps_size;

                memcpy(codec->extradata + pos, hevc_data->sei, hevc_data->sei_size);

                pos += hevc_data->sei_size;

                memset(codec->extradata + pos, 0, AV_INPUT_BUFFER_PADDING_SIZE);

            }

            av_freep(&hevc_data->vps);

            av_freep(&hevc_data->sps);

            av_freep(&hevc_data->pps);

            av_freep(&hevc_data->sei);

            hevc_data->vps_size = 0;

            hevc_data->sps_size = 0;

            hevc_data->pps_size = 0;

            hevc_data->sei_size = 0;

        }

        return ret;

    }

    return 0;

}

static int hevc_handle_packet(AVFormatContext *ctx, PayloadContext *rtp_hevc_ctx,

                              AVStream *st, AVPacket *pkt, uint32_t *timestamp,

                              const uint8_t *buf, int len, uint16_t seq,

                              int flags)

{

    const uint8_t *rtp_pl = buf;

    int tid, lid, nal_type;

    int first_fragment, last_fragment, fu_type;

    uint8_t new_nal_header[2];

    int res = 0;

    /* sanity check for size of input packet: 1 byte payload at least */

    if (len < RTP_HEVC_PAYLOAD_HEADER_SIZE + 1) {

        av_log(ctx, AV_LOG_ERROR, "Too short RTP/HEVC packet, got %d bytes\n", len);

        return AVERROR_INVALIDDATA;

    }

    /*

     * decode the HEVC payload header according to section 4 of draft version 6:

     *

     *    0                   1

     *    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5

     *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     *   |F|   Type    |  LayerId  | TID |

     *   +-------------+-----------------+

     *

     *      Forbidden zero (F): 1 bit

     *      NAL unit type (Type): 6 bits

     *      NUH layer ID (LayerId): 6 bits

     *      NUH temporal ID plus 1 (TID): 3 bits

     */

    nal_type =  (buf[0] >> 1) & 0x3f;

    lid  = ((buf[0] << 5) & 0x20) | ((buf[1] >> 3) & 0x1f);

    tid  =   buf[1] & 0x07;

    /* sanity check for correct layer ID */

    if (lid) {

        /* future scalable or 3D video coding extensions */

        avpriv_report_missing_feature(ctx, "Multi-layer HEVC coding\n");

        return AVERROR_PATCHWELCOME;

    }

    /* sanity check for correct temporal ID */

    if (!tid) {

        av_log(ctx, AV_LOG_ERROR, "Illegal temporal ID in RTP/HEVC packet\n");

        return AVERROR_INVALIDDATA;

    }

    /* sanity check for correct NAL unit type */

    if (nal_type > 50) {

        av_log(ctx, AV_LOG_ERROR, "Unsupported (HEVC) NAL type (%d)\n", nal_type);

        return AVERROR_INVALIDDATA;

    }

    switch (nal_type) {

    /* video parameter set (VPS) */

    case 32:

    /* sequence parameter set (SPS) */

    case 33:

    /* picture parameter set (PPS) */

    case 34:

    /*  supplemental enhancement information (SEI) */

    case 39:

    /* single NAL unit packet */

    default:

        /* create A/V packet */

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

            return res;

        /* A/V packet: copy start sequence */

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

        /* A/V packet: copy NAL unit data */

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

        break;

    /* aggregated packet (AP) - with two or more NAL units */

    case 48:

        /* pass the HEVC payload header */

        buf += RTP_HEVC_PAYLOAD_HEADER_SIZE;

        len -= RTP_HEVC_PAYLOAD_HEADER_SIZE;

        /* pass the HEVC DONL field */

        if (rtp_hevc_ctx->using_donl_field) {

            buf += RTP_HEVC_DONL_FIELD_SIZE;

            len -= RTP_HEVC_DONL_FIELD_SIZE;

        }

        res = ff_h264_handle_aggregated_packet(ctx, rtp_hevc_ctx, pkt, buf, len,

                                               rtp_hevc_ctx->using_donl_field ?

                                               RTP_HEVC_DOND_FIELD_SIZE : 0,

                                               NULL, 0);

        if (res < 0)

            return res;

        break;

    /* fragmentation unit (FU) */

    case 49:

        /* pass the HEVC payload header */

        buf += RTP_HEVC_PAYLOAD_HEADER_SIZE;

        len -= RTP_HEVC_PAYLOAD_HEADER_SIZE;

        /*

         *    decode the FU header

         *

         *     0 1 2 3 4 5 6 7

         *    +-+-+-+-+-+-+-+-+

         *    |S|E|  FuType   |

         *    +---------------+

         *

         *       Start fragment (S): 1 bit

         *       End fragment (E): 1 bit

         *       FuType: 6 bits

         */

        first_fragment = buf[0] & 0x80;

        last_fragment  = buf[0] & 0x40;

        fu_type        = buf[0] & 0x3f;

        /* pass the HEVC FU header */

        buf += RTP_HEVC_FU_HEADER_SIZE;

        len -= RTP_HEVC_FU_HEADER_SIZE;

        /* pass the HEVC DONL field */

        if (rtp_hevc_ctx->using_donl_field) {

            buf += RTP_HEVC_DONL_FIELD_SIZE;

            len -= RTP_HEVC_DONL_FIELD_SIZE;

        }

        av_log(ctx, AV_LOG_TRACE, " FU type %d with %d bytes\n", fu_type, len);

        /* sanity check for size of input packet: 1 byte payload at least */

        if (len <= 0) {

            if (len < 0) {

                av_log(ctx, AV_LOG_ERROR,

                       "Too short RTP/HEVC packet, got %d bytes of NAL unit type %d\n",

                       len, nal_type);

                return AVERROR_INVALIDDATA;

            } else {

                return AVERROR(EAGAIN);

            }

        }

        if (first_fragment && last_fragment) {

            av_log(ctx, AV_LOG_ERROR, "Illegal combination of S and E bit in RTP/HEVC packet\n");

            return AVERROR_INVALIDDATA;

        }

        new_nal_header[0] = (rtp_pl[0] & 0x81) | (fu_type << 1);

        new_nal_header[1] = rtp_pl[1];

        res = ff_h264_handle_frag_packet(pkt, buf, len, first_fragment,

                                         new_nal_header, sizeof(new_nal_header));

        break;

    /* PACI packet */

    case 50:

        /* Temporal scalability control information (TSCI) */

        avpriv_report_missing_feature(ctx, "PACI packets for RTP/HEVC\n");

        res = AVERROR_PATCHWELCOME;

        break;

    }

    pkt->stream_index = st->index;

    return res;

}

RTPDynamicProtocolHandler ff_hevc_dynamic_handler = {

    .enc_name         = "H265",

    .codec_type       = AVMEDIA_TYPE_VIDEO,

    .codec_id         = AV_CODEC_ID_HEVC,

    .need_parsing     = AVSTREAM_PARSE_FULL,

    .priv_data_size   = sizeof(PayloadContext),

    .parse_sdp_a_line = hevc_parse_sdp_line,

    .parse_packet     = hevc_handle_packet,

};