1/* 2 * Tele-typewriter demuxer 3 * Copyright (c) 2010 Peter Ross <pross@xvid.org> 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/** 23 * @file 24 * Tele-typewriter demuxer 25 */ 26 27#include "libavutil/intreadwrite.h" 28#include "libavutil/avstring.h" 29#include "libavutil/log.h" 30#include "libavutil/dict.h" 31#include "libavutil/opt.h" 32#include "libavutil/parseutils.h" 33#include "avformat.h" 34#include "internal.h" 35#include "sauce.h" 36 37typedef struct { 38 AVClass *class; 39 int chars_per_frame; 40 uint64_t fsize; /**< file size less metadata buffer */ 41 int width, height; /**< Set by a private option. */ 42 AVRational framerate; /**< Set by a private option. */ 43} TtyDemuxContext; 44 45/** 46 * Parse EFI header 47 */ 48static int efi_read(AVFormatContext *avctx, uint64_t start_pos) 49{ 50 TtyDemuxContext *s = avctx->priv_data; 51 AVIOContext *pb = avctx->pb; 52 char buf[37]; 53 int len; 54 55 avio_seek(pb, start_pos, SEEK_SET); 56 if (avio_r8(pb) != 0x1A) 57 return -1; 58 59#define GET_EFI_META(name,size) \ 60 len = avio_r8(pb); \ 61 if (len < 1 || len > size) \ 62 return -1; \ 63 if (avio_read(pb, buf, size) == size) { \ 64 buf[len] = 0; \ 65 av_dict_set(&avctx->metadata, name, buf, 0); \ 66 } 67 68 GET_EFI_META("filename", 12) 69 GET_EFI_META("title", 36) 70 71 s->fsize = start_pos; 72 return 0; 73} 74 75static int read_header(AVFormatContext *avctx) 76{ 77 TtyDemuxContext *s = avctx->priv_data; 78 int ret = 0; 79 AVStream *st = avformat_new_stream(avctx, NULL); 80 81 if (!st) { 82 ret = AVERROR(ENOMEM); 83 goto fail; 84 } 85 st->codec->codec_tag = 0; 86 st->codec->codec_type = AVMEDIA_TYPE_VIDEO; 87 st->codec->codec_id = AV_CODEC_ID_ANSI; 88 89 st->codec->width = s->width; 90 st->codec->height = s->height; 91 avpriv_set_pts_info(st, 60, s->framerate.den, s->framerate.num); 92 st->avg_frame_rate = s->framerate; 93 94 /* simulate tty display speed */ 95 s->chars_per_frame = FFMAX(av_q2d(st->time_base)*s->chars_per_frame, 1); 96 97 if (avctx->pb->seekable) { 98 s->fsize = avio_size(avctx->pb); 99 st->duration = (s->fsize + s->chars_per_frame - 1) / s->chars_per_frame; 100 101 if (ff_sauce_read(avctx, &s->fsize, 0, 0) < 0) 102 efi_read(avctx, s->fsize - 51); 103 104 avio_seek(avctx->pb, 0, SEEK_SET); 105 } 106 107fail: 108 return ret; 109} 110 111static int read_packet(AVFormatContext *avctx, AVPacket *pkt) 112{ 113 TtyDemuxContext *s = avctx->priv_data; 114 int n; 115 116 if (url_feof(avctx->pb)) 117 return AVERROR_EOF; 118 119 n = s->chars_per_frame; 120 if (s->fsize) { 121 // ignore metadata buffer 122 uint64_t p = avio_tell(avctx->pb); 123 if (p == s->fsize) 124 return AVERROR_EOF; 125 if (p + s->chars_per_frame > s->fsize) 126 n = s->fsize - p; 127 } 128 129 pkt->size = av_get_packet(avctx->pb, pkt, n); 130 if (pkt->size < 0) 131 return pkt->size; 132 pkt->flags |= AV_PKT_FLAG_KEY; 133 return 0; 134} 135 136#define OFFSET(x) offsetof(TtyDemuxContext, x) 137#define DEC AV_OPT_FLAG_DECODING_PARAM 138static const AVOption options[] = { 139 { "chars_per_frame", "", offsetof(TtyDemuxContext, chars_per_frame), AV_OPT_TYPE_INT, {.i64 = 6000}, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM}, 140 { "video_size", "A string describing frame size, such as 640x480 or hd720.", OFFSET(width), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, DEC }, 141 { "framerate", "", OFFSET(framerate), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, 0, DEC }, 142 { NULL }, 143}; 144 145static const AVClass tty_demuxer_class = { 146 .class_name = "TTY demuxer", 147 .item_name = av_default_item_name, 148 .option = options, 149 .version = LIBAVUTIL_VERSION_INT, 150}; 151 152AVInputFormat ff_tty_demuxer = { 153 .name = "tty", 154 .long_name = NULL_IF_CONFIG_SMALL("Tele-typewriter"), 155 .priv_data_size = sizeof(TtyDemuxContext), 156 .read_header = read_header, 157 .read_packet = read_packet, 158 .extensions = "ans,art,asc,diz,ice,nfo,txt,vt", 159 .priv_class = &tty_demuxer_class, 160}; 161