| 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 | |
| 29 | static 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 | |
| 47 | static 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 | |
| 63 | static 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 (avio_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 | |
| 94 | AVInputFormat 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 | }; |