libavformat/tty.c

   1 /*
   2  * Tele-typewriter demuxer
   3  * Copyright (c) 2010 Peter Ross <pross@xvid.org>
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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
  37 typedef struct {
  38     AVClass *class;
  39     int chars_per_frame;
  40     uint64_t fsize;  /**< file size less metadata buffer */
  41     char *video_size;/**< A string describing video size, set by a private option. */
  42     char *framerate; /**< Set by a private option. */
  43 } TtyDemuxContext;
  44
  45 /**
  46  * Parse EFI header
  47  */
  48 static 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
  75 static int read_header(AVFormatContext *avctx)
  76 {
  77     TtyDemuxContext *s = avctx->priv_data;
  78     int width = 0, height = 0, ret = 0;
  79     AVStream *st = avformat_new_stream(avctx, NULL);
  80     AVRational framerate;
  81
  82     if (!st) {
  83         ret = AVERROR(ENOMEM);
  84         goto fail;
  85     }
  86     st->codec->codec_tag   = 0;
  87     st->codec->codec_type  = AVMEDIA_TYPE_VIDEO;
  88     st->codec->codec_id    = AV_CODEC_ID_ANSI;
  89
  90     if (s->video_size && (ret = av_parse_video_size(&width, &height, s->video_size)) < 0) {
  91         av_log (avctx, AV_LOG_ERROR, "Couldn't parse video size.\n");
  92         goto fail;
  93     }
  94     if ((ret = av_parse_video_rate(&framerate, s->framerate)) < 0) {
  95         av_log(avctx, AV_LOG_ERROR, "Could not parse framerate: %s.\n", s->framerate);
  96         goto fail;
  97     }
  98     st->codec->width  = width;
  99     st->codec->height = height;
 100     avpriv_set_pts_info(st, 60, framerate.den, framerate.num);
 101
 102     /* simulate tty display speed */
 103     s->chars_per_frame = FFMAX(av_q2d(st->time_base)*s->chars_per_frame, 1);
 104
 105     if (avctx->pb->seekable) {
 106         s->fsize = avio_size(avctx->pb);
 107         st->duration = (s->fsize + s->chars_per_frame - 1) / s->chars_per_frame;
 108
 109         if (ff_sauce_read(avctx, &s->fsize, 0, 0) < 0)
 110             efi_read(avctx, s->fsize - 51);
 111
 112         avio_seek(avctx->pb, 0, SEEK_SET);
 113     }
 114
 115 fail:
 116     return ret;
 117 }
 118
 119 static int read_packet(AVFormatContext *avctx, AVPacket *pkt)
 120 {
 121     TtyDemuxContext *s = avctx->priv_data;
 122     int n;
 123
 124     if (avctx->pb->eof_reached)
 125         return AVERROR_EOF;
 126
 127     n = s->chars_per_frame;
 128     if (s->fsize) {
 129         // ignore metadata buffer
 130         uint64_t p = avio_tell(avctx->pb);
 131         if (p + s->chars_per_frame > s->fsize)
 132             n = s->fsize - p;
 133     }
 134
 135     pkt->size = av_get_packet(avctx->pb, pkt, n);
 136     if (pkt->size <= 0)
 137         return AVERROR(EIO);
 138     pkt->flags |= AV_PKT_FLAG_KEY;
 139     return 0;
 140 }
 141
 142 #define OFFSET(x) offsetof(TtyDemuxContext, x)
 143 #define DEC AV_OPT_FLAG_DECODING_PARAM
 144 static const AVOption options[] = {
 145     { "chars_per_frame", "", offsetof(TtyDemuxContext, chars_per_frame), AV_OPT_TYPE_INT, {.i64 = 6000}, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM},
 146     { "video_size", "A string describing frame size, such as 640x480 or hd720.", OFFSET(video_size), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },
 147     { "framerate", "", OFFSET(framerate), AV_OPT_TYPE_STRING, {.str = "25"}, 0, 0, DEC },
 148     { NULL },
 149 };
 150
 151 static const AVClass tty_demuxer_class = {
 152     .class_name     = "TTY demuxer",
 153     .item_name      = av_default_item_name,
 154     .option         = options,
 155     .version        = LIBAVUTIL_VERSION_INT,
 156 };
 157
 158 AVInputFormat ff_tty_demuxer = {
 159     .name           = "tty",
 160     .long_name      = NULL_IF_CONFIG_SMALL("Tele-typewriter"),
 161     .priv_data_size = sizeof(TtyDemuxContext),
 162     .read_header    = read_header,
 163     .read_packet    = read_packet,
 164     .extensions     = "ans,art,asc,diz,ice,nfo,txt,vt",
 165     .priv_class     = &tty_demuxer_class,
 166 };