libavformat/rtpdec_vc2hq.c

   1 /*
   2  * RTP parser for VC-2 HQ payload format (draft version 1) - experimental
   3  * Copyright (c) 2016 Thomas Volkert <thomas@netzeal.de>
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "libavutil/intreadwrite.h"
  23 #include "libavcodec/dirac.h"
  24
  25 #include "avio_internal.h"
  26 #include "rtpdec_formats.h"
  27
  28 #define RTP_VC2HQ_PL_HEADER_SIZE             4
  29
  30 #define DIRAC_DATA_UNIT_HEADER_SIZE          13
  31 #define DIRAC_PIC_NR_SIZE                    4
  32 #define DIRAC_RTP_PCODE_HQ_PIC_FRAGMENT      0xEC
  33
  34 struct PayloadContext {
  35     AVIOContext *buf;
  36     uint32_t    frame_size;
  37     uint32_t    frame_nr;
  38     uint32_t    timestamp;
  39     uint32_t    last_unit_size;
  40     int         seen_sequence_header;
  41 };
  42
  43 static const uint8_t start_sequence[] = { 'B', 'B', 'C', 'D' };
  44
  45 static void fill_parse_info_header(PayloadContext *pl_ctx, uint8_t *buf,
  46                                    uint8_t parse_code, uint32_t data_unit_size)
  47 {
  48     memcpy(buf, start_sequence, sizeof(start_sequence));
  49     buf[4]  = parse_code;
  50     AV_WB32(&buf[5], data_unit_size);
  51     AV_WB32(&buf[9], pl_ctx->last_unit_size);
  52
  53     pl_ctx->last_unit_size = data_unit_size;
  54 }
  55
  56 static int vc2hq_handle_sequence_header(PayloadContext *pl_ctx, AVStream *st, AVPacket *pkt,
  57                                         const uint8_t *buf, int len)
  58 {
  59     int res;
  60     uint32_t size = DIRAC_DATA_UNIT_HEADER_SIZE + len;
  61
  62     if ((res = av_new_packet(pkt, DIRAC_DATA_UNIT_HEADER_SIZE + len)) < 0)
  63         return res;
  64
  65     fill_parse_info_header(pl_ctx, pkt->data, 0x00, size);
  66     /* payload of seq. header */
  67     memcpy(pkt->data + DIRAC_DATA_UNIT_HEADER_SIZE, buf, len);
  68     pkt->stream_index = st->index;
  69
  70     pl_ctx->seen_sequence_header = 1;
  71
  72     return 0;
  73 }
  74
  75 static int vc2hq_mark_end_of_sequence(PayloadContext *pl_ctx, AVStream *st, AVPacket *pkt)
  76 {
  77     int res;
  78     uint32_t size = 0;
  79
  80     /* create A/V packet */
  81     if ((res = av_new_packet(pkt, DIRAC_DATA_UNIT_HEADER_SIZE)) < 0)
  82         return res;
  83
  84     fill_parse_info_header(pl_ctx, pkt->data, 0x10, size);
  85     pkt->stream_index = st->index;
  86
  87     pl_ctx->seen_sequence_header = 0;
  88
  89     return 0;
  90 }
  91
  92 static int vc2hq_handle_frame_fragment(AVFormatContext *ctx, PayloadContext *pl_ctx, AVStream *st,
  93                                        AVPacket *pkt, uint32_t *timestamp, const uint8_t *buf, int len,
  94                                        int flags)
  95 {
  96     int res;
  97     uint32_t pic_nr;
  98     uint16_t frag_len;
  99     uint16_t no_slices;
 100
 101     /* sanity check for size of input packet: 16 bytes header in any case as minimum */
 102     if (len < 16) {
 103         av_log(ctx, AV_LOG_ERROR, "Too short RTP/VC2hq packet, got %d bytes\n", len);
 104         return AVERROR_INVALIDDATA;
 105     }
 106
 107     pic_nr = AV_RB32(&buf[4]);
 108     frag_len = AV_RB16(&buf[12]);
 109     no_slices = AV_RB16(&buf[14]);
 110
 111     if (pl_ctx->buf && pl_ctx->frame_nr != pic_nr) {
 112         av_log(ctx, AV_LOG_WARNING, "Dropping buffered RTP/VC2hq packet fragments - non-continuous picture numbers\n");
 113         ffio_free_dyn_buf(&pl_ctx->buf);
 114     }
 115
 116     /* transform parameters? */
 117     if (no_slices == 0) {
 118         if (len < frag_len + 16) {
 119             av_log(ctx, AV_LOG_ERROR, "Too short RTP/VC2hq packet, got %d bytes\n", len);
 120             return AVERROR_INVALIDDATA;
 121         }
 122
 123         /* start frame buffering with new dynamic buffer */
 124         if (!pl_ctx->buf) {
 125
 126             res = avio_open_dyn_buf(&pl_ctx->buf);
 127             if (res < 0)
 128                 return res;
 129
 130             /* reserve memory for frame header */
 131             res = avio_seek(pl_ctx->buf, DIRAC_DATA_UNIT_HEADER_SIZE + DIRAC_PIC_NR_SIZE, SEEK_SET);
 132             if (res < 0)
 133                 return res;
 134
 135             pl_ctx->frame_nr = pic_nr;
 136             pl_ctx->timestamp = *timestamp;
 137             pl_ctx->frame_size = DIRAC_DATA_UNIT_HEADER_SIZE + DIRAC_PIC_NR_SIZE;
 138         }
 139
 140         avio_write(pl_ctx->buf, buf + 16 /* skip pl header */, frag_len);
 141         pl_ctx->frame_size += frag_len;
 142
 143         return AVERROR(EAGAIN);
 144     } else {
 145         if (len < frag_len + 20) {
 146             av_log(ctx, AV_LOG_ERROR, "Too short RTP/VC2hq packet, got %d bytes\n", len);
 147             return AVERROR_INVALIDDATA;
 148         }
 149
 150         /* transform parameters were missed, no buffer available */
 151         if (!pl_ctx->buf)
 152             return AVERROR_INVALIDDATA;
 153
 154         avio_write(pl_ctx->buf, buf + 20 /* skip pl header */, frag_len);
 155         pl_ctx->frame_size += frag_len;
 156
 157         /* RTP marker bit means: last fragment of current frame was received;
 158            otherwise, an additional fragment is needed for the current frame */
 159         if (!(flags & RTP_FLAG_MARKER))
 160             return AVERROR(EAGAIN);
 161     }
 162
 163     /* close frame buffering and create A/V packet */
 164     res = ff_rtp_finalize_packet(pkt, &pl_ctx->buf, st->index);
 165     if (res < 0)
 166         return res;
 167
 168     fill_parse_info_header(pl_ctx, pkt->data, DIRAC_PCODE_PICTURE_HQ, pl_ctx->frame_size);
 169     AV_WB32(&pkt->data[13], pl_ctx->frame_nr);
 170
 171     pl_ctx->frame_size = 0;
 172
 173     return 0;
 174 }
 175
 176 static int vc2hq_handle_packet(AVFormatContext *ctx, PayloadContext *pl_ctx,
 177                                AVStream *st, AVPacket *pkt, uint32_t *timestamp,
 178                                const uint8_t *buf, int len, uint16_t seq,
 179                                int flags)
 180 {
 181     uint8_t parse_code = 0;
 182     int res = 0;
 183
 184     if (pl_ctx->buf && pl_ctx->timestamp != *timestamp) {
 185         av_log(ctx, AV_LOG_WARNING, "Dropping buffered RTP/VC2hq packet fragments - non-continuous timestamps\n");
 186         ffio_free_dyn_buf(&pl_ctx->buf);
 187         pl_ctx->frame_size = 0;
 188     }
 189
 190     /* sanity check for size of input packet: needed header data as minimum */
 191     if (len < RTP_VC2HQ_PL_HEADER_SIZE) {
 192         av_log(ctx, AV_LOG_ERROR, "Too short RTP/VC2hq packet, got %d bytes\n", len);
 193         return AVERROR_INVALIDDATA;
 194     }
 195
 196     parse_code = buf[3];
 197
 198     /* wait for next sequence header? */
 199     if (pl_ctx->seen_sequence_header || parse_code == DIRAC_PCODE_SEQ_HEADER) {
 200         switch(parse_code) {
 201         /* sequence header */
 202         case DIRAC_PCODE_SEQ_HEADER:
 203             res = vc2hq_handle_sequence_header(pl_ctx, st, pkt, buf + RTP_VC2HQ_PL_HEADER_SIZE, len - RTP_VC2HQ_PL_HEADER_SIZE);
 204             break;
 205         /* end of sequence */
 206         case DIRAC_PCODE_END_SEQ:
 207             res = vc2hq_mark_end_of_sequence(pl_ctx, st, pkt);
 208             break;
 209         /* HQ picture fragment */
 210         case DIRAC_RTP_PCODE_HQ_PIC_FRAGMENT:
 211             res = vc2hq_handle_frame_fragment(ctx, pl_ctx, st, pkt, timestamp, buf, len, flags);
 212             break;
 213         }
 214     }
 215
 216     return res;
 217 }
 218
 219 const RTPDynamicProtocolHandler ff_vc2hq_dynamic_handler = {
 220     .enc_name         = "VC2",
 221     .codec_type       = AVMEDIA_TYPE_VIDEO,
 222     .codec_id         = AV_CODEC_ID_DIRAC,
 223     .priv_data_size   = sizeof(PayloadContext),
 224     .parse_packet     = vc2hq_handle_packet
 225 };