1/* 2 * NC camera feed demuxer 3 * Copyright (c) 2009 Nicolas Martin (martinic at iro dot umontreal dot ca) 4 * Edouard Auvinet 5 * 6 * This file is part of FFmpeg. 7 * 8 * FFmpeg is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; either 11 * version 2.1 of the License, or (at your option) any later version. 12 * 13 * FFmpeg is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 * Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with FFmpeg; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 */ 22 23#include "libavutil/intreadwrite.h" 24#include "avformat.h" 25#include "internal.h" 26 27#define NC_VIDEO_FLAG 0x1A5 28 29static int nc_probe(AVProbeData *probe_packet) 30{ 31 int size; 32 33 if (AV_RB32(probe_packet->buf) != NC_VIDEO_FLAG) 34 return 0; 35 36 size = AV_RL16(probe_packet->buf + 5); 37 38 if (size + 20 > probe_packet->buf_size) 39 return AVPROBE_SCORE_MAX/4; 40 41 if (AV_RB32(probe_packet->buf+16+size) == NC_VIDEO_FLAG) 42 return AVPROBE_SCORE_MAX; 43 44 return 0; 45} 46 47static int nc_read_header(AVFormatContext *s) 48{ 49 AVStream *st = avformat_new_stream(s, NULL); 50 51 if (!st) 52 return AVERROR(ENOMEM); 53 54 st->codec->codec_type = AVMEDIA_TYPE_VIDEO; 55 st->codec->codec_id = AV_CODEC_ID_MPEG4; 56 st->need_parsing = AVSTREAM_PARSE_FULL; 57 58 avpriv_set_pts_info(st, 64, 1, 100); 59 60 return 0; 61} 62 63static int nc_read_packet(AVFormatContext *s, AVPacket *pkt) 64{ 65 int size; 66 int ret; 67 68 uint32_t state=-1; 69 while (state != NC_VIDEO_FLAG) { 70 if (url_feof(s->pb)) 71 return AVERROR(EIO); 72 state = (state<<8) + avio_r8(s->pb); 73 } 74 75 avio_r8(s->pb); 76 size = avio_rl16(s->pb); 77 avio_skip(s->pb, 9); 78 79 if (size == 0) { 80 av_log(s, AV_LOG_DEBUG, "Next packet size is zero\n"); 81 return AVERROR(EAGAIN); 82 } 83 84 ret = av_get_packet(s->pb, pkt, size); 85 if (ret != size) { 86 if (ret > 0) av_free_packet(pkt); 87 return AVERROR(EIO); 88 } 89 90 pkt->stream_index = 0; 91 return size; 92} 93 94AVInputFormat ff_nc_demuxer = { 95 .name = "nc", 96 .long_name = NULL_IF_CONFIG_SMALL("NC camera feed"), 97 .read_probe = nc_probe, 98 .read_header = nc_read_header, 99 .read_packet = nc_read_packet, 100 .extensions = "v", 101}; 102