/*
  * TechnoTrend PVA (.pva) demuxer
  * Copyright (c) 2007, 2008 Ivo van Poorten
  *
  * 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 "avformat.h"

 #include "internal.h"

 #include "mpeg.h"

 
 #define PVA_MAX_PAYLOAD_LENGTH  0x17f8
 #define PVA_VIDEO_PAYLOAD       0x01
 #define PVA_AUDIO_PAYLOAD       0x02
 #define PVA_MAGIC               (('A' << 8) + 'V')
 

 typedef struct PVAContext {

     int continue_pes;
 } PVAContext;
 

 static int pva_check(const uint8_t *p) {

     int length = AV_RB16(p + 6);
     if (AV_RB16(p) != PVA_MAGIC || !p[2] || p[2] > 2 || p[4] != 0x55 ||
         (p[5] & 0xe0) || length > PVA_MAX_PAYLOAD_LENGTH)
         return -1;
     return length + 8;
 }
 

 static int pva_probe(AVProbeData * pd) {

     const unsigned char *buf = pd->buf;

     int len = pva_check(buf);
 
     if (len < 0)
         return 0;

     if (pd->buf_size >= len + 8 &&
         pva_check(buf + len) >= 0)

         return AVPROBE_SCORE_EXTENSION;

     return AVPROBE_SCORE_MAX / 4;

 }
 

 static int pva_read_header(AVFormatContext *s) {

     AVStream *st;
 

     if (!(st = avformat_new_stream(s, NULL)))

         return AVERROR(ENOMEM);

     st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
     st->codecpar->codec_id   = AV_CODEC_ID_MPEG2VIDEO;

     st->need_parsing      = AVSTREAM_PARSE_FULL;

     avpriv_set_pts_info(st, 32, 1, 90000);

     av_add_index_entry(st, 0, 0, 0, 0, AVINDEX_KEYFRAME);

     if (!(st = avformat_new_stream(s, NULL)))

         return AVERROR(ENOMEM);

     st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
     st->codecpar->codec_id   = AV_CODEC_ID_MP2;

     st->need_parsing      = AVSTREAM_PARSE_FULL;

     avpriv_set_pts_info(st, 33, 1, 90000);

     av_add_index_entry(st, 0, 0, 0, 0, AVINDEX_KEYFRAME);

 
     /* the parameters will be extracted from the compressed bitstream */
     return 0;
 }
 

 #define pva_log if (read_packet) av_log
 
 static int read_part_of_packet(AVFormatContext *s, int64_t *pts,
                                int *len, int *strid, int read_packet) {

     AVIOContext *pb = s->pb;

     PVAContext *pvactx = s->priv_data;

     int syncword, streamid, reserved, flags, length, pts_flag;
     int64_t pva_pts = AV_NOPTS_VALUE, startpos;

     int ret;

 recover:

     startpos = avio_tell(pb);

     syncword = avio_rb16(pb);
     streamid = avio_r8(pb);
     avio_r8(pb);               /* counter not used */
     reserved = avio_r8(pb);
     flags    = avio_r8(pb);
     length   = avio_rb16(pb);

     pts_flag = flags & 0x10;

 
     if (syncword != PVA_MAGIC) {

         pva_log(s, AV_LOG_ERROR, "invalid syncword\n");

         return AVERROR(EIO);
     }

     if (streamid != PVA_VIDEO_PAYLOAD && streamid != PVA_AUDIO_PAYLOAD) {

         pva_log(s, AV_LOG_ERROR, "invalid streamid\n");

         return AVERROR(EIO);
     }

     if (reserved != 0x55) {

         pva_log(s, AV_LOG_WARNING, "expected reserved byte to be 0x55\n");

     }
     if (length > PVA_MAX_PAYLOAD_LENGTH) {

         pva_log(s, AV_LOG_ERROR, "invalid payload length %u\n", length);

         return AVERROR(EIO);
     }
 
     if (streamid == PVA_VIDEO_PAYLOAD && pts_flag) {

         pva_pts = avio_rb32(pb);

         length -= 4;
     } else if (streamid == PVA_AUDIO_PAYLOAD) {
         /* PVA Audio Packets either start with a signaled PES packet or
          * are a continuation of the previous PES packet. New PES packets
          * always start at the beginning of a PVA Packet, never somewhere in
          * the middle. */
         if (!pvactx->continue_pes) {
             int pes_signal, pes_header_data_length, pes_packet_length,
                 pes_flags;
             unsigned char pes_header_data[256];
 

             pes_signal             = avio_rb24(pb);
             avio_r8(pb);
             pes_packet_length      = avio_rb16(pb);
             pes_flags              = avio_rb16(pb);
             pes_header_data_length = avio_r8(pb);

             if (avio_feof(pb)) {
                 return AVERROR_EOF;
             }
 

             if (pes_signal != 1 || pes_header_data_length == 0) {
                 pva_log(s, AV_LOG_WARNING, "expected non empty signaled PES packet, "

                                           "trying to recover\n");

                 avio_skip(pb, length - 9);

                 if (!read_packet)
                     return AVERROR(EIO);

                 goto recover;

             }
 

             ret = avio_read(pb, pes_header_data, pes_header_data_length);
             if (ret != pes_header_data_length)
                 return ret < 0 ? ret : AVERROR_INVALIDDATA;

             length -= 9 + pes_header_data_length;
 
             pes_packet_length -= 3 + pes_header_data_length;
 
             pvactx->continue_pes = pes_packet_length;
 

             if (pes_flags & 0x80 && (pes_header_data[0] & 0xf0) == 0x20) {
                 if (pes_header_data_length < 5) {
                     pva_log(s, AV_LOG_ERROR, "header too short\n");
                     avio_skip(pb, length);
                     return AVERROR_INVALIDDATA;
                 }

                 pva_pts = ff_parse_pes_pts(pes_header_data);

             }

         }
 
         pvactx->continue_pes -= length;
 
         if (pvactx->continue_pes < 0) {

             pva_log(s, AV_LOG_WARNING, "audio data corruption\n");

             pvactx->continue_pes = 0;
         }
     }
 

     if (pva_pts != AV_NOPTS_VALUE)
         av_add_index_entry(s->streams[streamid-1], startpos, pva_pts, 0, 0, AVINDEX_KEYFRAME);
 
     *pts   = pva_pts;
     *len   = length;
     *strid = streamid;
     return 0;
 }
 
 static int pva_read_packet(AVFormatContext *s, AVPacket *pkt) {

     AVIOContext *pb = s->pb;

     int64_t pva_pts;
     int ret, length, streamid;
 
     if (read_part_of_packet(s, &pva_pts, &length, &streamid, 1) < 0 ||
        (ret = av_get_packet(pb, pkt, length)) <= 0)

         return AVERROR(EIO);
 
     pkt->stream_index = streamid - 1;

     pkt->pts = pva_pts;

 
     return ret;
 }
 

 static int64_t pva_read_timestamp(struct AVFormatContext *s, int stream_index,
                                           int64_t *pos, int64_t pos_limit) {

     AVIOContext *pb = s->pb;

     PVAContext *pvactx = s->priv_data;
     int length, streamid;

     int64_t res = AV_NOPTS_VALUE;

 
     pos_limit = FFMIN(*pos+PVA_MAX_PAYLOAD_LENGTH*8, (uint64_t)*pos+pos_limit);
 
     while (*pos < pos_limit) {
         res = AV_NOPTS_VALUE;

         avio_seek(pb, *pos, SEEK_SET);

 
         pvactx->continue_pes = 0;
         if (read_part_of_packet(s, &res, &length, &streamid, 0)) {
             (*pos)++;
             continue;
         }
         if (streamid - 1 != stream_index || res == AV_NOPTS_VALUE) {

             *pos = avio_tell(pb) + length;

             continue;
         }
         break;
     }
 
     pvactx->continue_pes = 0;
     return res;
 }
 

 AVInputFormat ff_pva_demuxer = {

     .name           = "pva",

     .long_name      = NULL_IF_CONFIG_SMALL("TechnoTrend PVA"),

     .priv_data_size = sizeof(PVAContext),
     .read_probe     = pva_probe,
     .read_header    = pva_read_header,
     .read_packet    = pva_read_packet,

     .read_timestamp = pva_read_timestamp,

 };