Tele-typewriter demuxer

Originally committed as revision 24301 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 131 insertions, 0 deletions

diff --git a/libavformat/tty.c b/libavformat/tty.c
new file mode 100644
index 0000000000..03a4f16d76
--- /dev/null
+++ b/libavformat/tty.c
@@ -0,0 +1,131 @@
+/*
+ * @file
+ * Tele-typewriter demuxer
+ * Copyright (c) 2010 Peter Ross <pross@xvid.org>
+ *
+ * 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 "libavutil/intreadwrite.h"
+#include "libavutil/avstring.h"
+#include "avformat.h"
+#include "sauce.h"
+#include <strings.h>
+
+#define LINE_RATE 6000 /* characters per second */
+
+typedef struct {
+    int chars_per_frame;
+    uint64_t fsize;  /** file size less metadata buffer */
+} TtyDemuxContext;
+
+/**
+ * Parse EFI header
+ */
+static int efi_read(AVFormatContext *avctx, uint64_t start_pos)
+{
+    TtyDemuxContext *s = avctx->priv_data;
+    ByteIOContext *pb = avctx->pb;
+    char buf[37];
+    int len;
+
+    url_fseek(pb, start_pos, SEEK_SET);
+    if (get_byte(pb) != 0x1A)
+        return -1;
+
+#define GET_EFI_META(name,size) \
+    len = get_byte(pb); \
+    if (len < 1 || len > size) \
+        return -1; \
+    if (get_buffer(pb, buf, size) == size) { \
+        buf[len] = 0; \
+        av_metadata_set2(&avctx->metadata, name, buf, 0); \
+    }
+
+    GET_EFI_META("filename", 12)
+    GET_EFI_META("title",    36)
+
+    s->fsize = start_pos;
+    return 0;
+}
+
+static int read_header(AVFormatContext *avctx,
+                       AVFormatParameters *ap)
+{
+    TtyDemuxContext *s = avctx->priv_data;
+    AVStream *st = av_new_stream(avctx, 0);
+    if (!st)
+        return AVERROR(ENOMEM);
+    st->codec->codec_tag   = 0;
+    st->codec->codec_type  = CODEC_TYPE_VIDEO;
+    st->codec->codec_id    = CODEC_ID_ANSI;
+    if (ap->width)  st->codec->width  = ap->width;
+    if (ap->height) st->codec->height = ap->height;
+
+    if (!ap->time_base.num) {
+        av_set_pts_info(st, 60, 1, 25);
+    } else {
+        av_set_pts_info(st, 60, ap->time_base.num, ap->time_base.den);
+    }
+
+    /* simulate tty display speed */
+    s->chars_per_frame = FFMAX(av_q2d(st->time_base) * (ap->sample_rate ? ap->sample_rate : LINE_RATE), 1);
+
+    if (!url_is_streamed(avctx->pb)) {
+        s->fsize = url_fsize(avctx->pb);
+        st->duration = (s->fsize + s->chars_per_frame - 1) / s->chars_per_frame;
+
+        if (ff_sauce_read(avctx, &s->fsize, 0, 0) < 0)
+            efi_read(avctx, s->fsize - 51);
+
+        url_fseek(avctx->pb, 0, SEEK_SET);
+    }
+
+    return 0;
+}
+
+static int read_packet(AVFormatContext *avctx, AVPacket *pkt)
+{
+    TtyDemuxContext *s = avctx->priv_data;
+    int n;
+
+    if (url_feof(avctx->pb))
+        return AVERROR_EOF;
+
+    n = s->chars_per_frame;
+    if (s->fsize) {
+        // ignore metadata buffer
+        uint64_t p = url_ftell(avctx->pb);
+        if (p + s->chars_per_frame > s->fsize)
+            n = s->fsize - p;
+    }
+
+    pkt->size = av_get_packet(avctx->pb, pkt, n);
+    if (pkt->size <= 0)
+        return AVERROR(EIO);
+    pkt->flags |= PKT_FLAG_KEY;
+    return 0;
+}
+
+AVInputFormat tty_demuxer = {
+    .name           = "tty",
+    .long_name      = NULL_IF_CONFIG_SMALL("Tele-typewriter"),
+    .priv_data_size = sizeof(TtyDemuxContext),
+    .read_header    = read_header,
+    .read_packet    = read_packet,
+    .extensions     = "ans,art,asc,diz,ice,nfo,txt,vt",
+};