/*
  * RTP parser for DV payload format (RFC 6469)
  * Copyright (c) 2015 Thomas Volkert <thomas@homer-conferencing.com>
  *
  * 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/avstring.h"

 #include "libavcodec/bytestream.h"
 

 #include "avio_internal.h"

 #include "rtpdec_formats.h"
 
 struct PayloadContext {
     AVIOContext *buf;
     uint32_t    timestamp;
     int         bundled_audio;
 };
 

 static av_cold void dv_close_context(PayloadContext *data)

 {

     ffio_free_dyn_buf(&data->buf);

 }
 
 static av_cold int dv_sdp_parse_fmtp_config(AVFormatContext *s,
                                             AVStream *stream,
                                             PayloadContext *dv_data,

                                             const char *attr, const char *value)

 {
     /* does the DV stream include audio? */

     if (!strcmp(attr, "audio") && !strcmp(value, "bundled"))

         dv_data->bundled_audio = 1;
 
     /* extract the DV profile */
     if (!strcmp(attr, "encode")) {
         /* SD-VCR/525-60 */
         /* SD-VCR/625-50 */
         /* HD-VCR/1125-60 */
         /* HD-VCR/1250-50 */
         /* SDL-VCR/525-60 */
         /* SDL-VCR/625-50 */
         /* 314M-25/525-60 */
         /* 314M-25/625-50 */
         /* 314M-50/525-60 */
         /* 314M-50/625-50 */
         /* 370M/1080-60i */
         /* 370M/1080-50i */
         /* 370M/720-60p */
         /* 370M/720-50p */
         /* 306M/525-60 (for backward compatibility) */
         /* 306M/625-50 (for backward compatibility) */
     }
 
     return 0;
 }
 
 static av_cold int dv_parse_sdp_line(AVFormatContext *ctx, int st_index,
                                      PayloadContext *dv_data, const char *line)
 {
     AVStream *current_stream;
     const char *sdp_line_ptr = line;
 
     if (st_index < 0)
         return 0;
 
     current_stream = ctx->streams[st_index];
 
     if (av_strstart(sdp_line_ptr, "fmtp:", &sdp_line_ptr)) {
         return ff_parse_fmtp(ctx, current_stream, dv_data, sdp_line_ptr,
                              dv_sdp_parse_fmtp_config);
     }
 
     return 0;
 }
 
 static int dv_handle_packet(AVFormatContext *ctx, PayloadContext *rtp_dv_ctx,
                             AVStream *st, AVPacket *pkt, uint32_t *timestamp,
                             const uint8_t *buf, int len, uint16_t seq,
                             int flags)
 {
     int res = 0;
 
     /* drop data of previous packets in case of non-continuous (lossy) packet stream */
     if (rtp_dv_ctx->buf && rtp_dv_ctx->timestamp != *timestamp) {

         ffio_free_dyn_buf(&rtp_dv_ctx->buf);

     }
 
     /* sanity check for size of input packet: 1 byte payload at least */
     if (len < 1) {
         av_log(ctx, AV_LOG_ERROR, "Too short RTP/DV packet, got %d bytes\n", len);
         return AVERROR_INVALIDDATA;
     }
 
     /* start frame buffering with new dynamic buffer */
     if (!rtp_dv_ctx->buf) {
         res = avio_open_dyn_buf(&rtp_dv_ctx->buf);
         if (res < 0)
             return res;
         /* update the timestamp in the frame packet with the one from the RTP packet */
         rtp_dv_ctx->timestamp = *timestamp;
     }
 
     /* write the fragment to the dyn. buffer */
     avio_write(rtp_dv_ctx->buf, buf, len);
 
     /* RTP marker bit means: last fragment of current frame was received;
        otherwise, an additional fragment is needed for the current frame */
     if (!(flags & RTP_FLAG_MARKER))
         return AVERROR(EAGAIN);
 
     /* close frame buffering and create resulting A/V packet */
     res = ff_rtp_finalize_packet(pkt, &rtp_dv_ctx->buf, st->index);
     if (res < 0)
         return res;
 
     return 0;
 }
 
 RTPDynamicProtocolHandler ff_dv_dynamic_handler = {
     .enc_name         = "DV",
     .codec_type       = AVMEDIA_TYPE_VIDEO,
     .codec_id         = AV_CODEC_ID_DVVIDEO,

     .need_parsing     = AVSTREAM_PARSE_FULL,

     .parse_sdp_a_line = dv_parse_sdp_line,

     .priv_data_size   = sizeof(PayloadContext),

     .close             = dv_close_context,

     .parse_packet     = dv_handle_packet,

 };