avformat: add MCC demuxer

Fixes #7680

1 files changed, 238 insertions, 0 deletions

diff --git a/libavformat/mccdec.c b/libavformat/mccdec.c
new file mode 100644
index 0000000000..874ff45cdf
--- /dev/null
+++ b/libavformat/mccdec.c
@@ -0,0 +1,238 @@
+/*
+ * MCC subtitle demuxer
+ * Copyright (c) 2020 Paul B Mahol
+ *
+ * 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 "avformat.h"
+#include "internal.h"
+#include "subtitles.h"
+#include "libavutil/avstring.h"
+#include "libavutil/bprint.h"
+#include "libavutil/intreadwrite.h"
+
+typedef struct MCCContext {
+    FFDemuxSubtitlesQueue q;
+} MCCContext;
+
+static int mcc_probe(const AVProbeData *p)
+{
+    char buf[28];
+    FFTextReader tr;
+
+    ff_text_init_buf(&tr, p->buf, p->buf_size);
+
+    while (ff_text_peek_r8(&tr) == '\r' || ff_text_peek_r8(&tr) == '\n')
+        ff_text_r8(&tr);
+
+    ff_text_read(&tr, buf, sizeof(buf));
+
+    if (!memcmp(buf, "File Format=MacCaption_MCC V", 28))
+        return AVPROBE_SCORE_MAX;
+
+    return 0;
+}
+
+static int convert(uint8_t x)
+{
+    if (x >= 'a')
+        x -= 87;
+    else if (x >= 'A')
+        x -= 55;
+    else
+        x -= '0';
+    return x;
+}
+
+typedef struct alias {
+    uint8_t key;
+    int len;
+    const char *value;
+} alias;
+
+static const alias aliases[20] = {
+    { .key = 16, .len =  3, .value = "\xFA\x0\x0", },
+    { .key = 17, .len =  6, .value = "\xFA\x0\x0\xFA\x0\x0", },
+    { .key = 18, .len =  9, .value = "\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0", },
+    { .key = 19, .len = 12, .value = "\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0", },
+    { .key = 20, .len = 15, .value = "\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0", },
+    { .key = 21, .len = 18, .value = "\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0", },
+    { .key = 22, .len = 21, .value = "\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0", },
+    { .key = 23, .len = 24, .value = "\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0", },
+    { .key = 24, .len = 27, .value = "\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0\xFA\x0\x0", },
+    { .key = 25, .len =  3, .value = "\xFB\x80\x80", },
+    { .key = 26, .len =  3, .value = "\xFC\x80\x80", },
+    { .key = 27, .len =  3, .value = "\xFD\x80\x80", },
+    { .key = 28, .len =  2, .value = "\x96\x69", },
+    { .key = 29, .len =  2, .value = "\x61\x01", },
+    { .key = 30, .len =  3, .value = "\xFC\x80\x80", },
+    { .key = 31, .len =  3, .value = "\xFC\x80\x80", },
+    { .key = 32, .len =  4, .value = "\xE1\x00\x00\x00", },
+    { .key = 33, .len =  0, .value = NULL, },
+    { .key = 34, .len =  0, .value = NULL, },
+    { .key = 35, .len =  1, .value = "\x0", },
+};
+
+static int mcc_read_header(AVFormatContext *s)
+{
+    MCCContext *mcc = s->priv_data;
+    AVStream *st = avformat_new_stream(s, NULL);
+    AVRational rate;
+    int64_t ts, pos;
+    uint8_t out[4096];
+    char line[4096];
+    FFTextReader tr;
+    int ret = 0;
+
+    ff_text_init_avio(s, &tr, s->pb);
+
+    if (!st)
+        return AVERROR(ENOMEM);
+    st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
+    st->codecpar->codec_id   = AV_CODEC_ID_EIA_608;
+    avpriv_set_pts_info(st, 64, 1, 30);
+
+    while (!ff_text_eof(&tr)) {
+        int hh, mm, ss, fs, i = 0, j = 0;
+        int start = 12, count = 0;
+        AVPacket *sub;
+        char *lline;
+
+        ff_subtitles_read_line(&tr, line, sizeof(line));
+        if (!strncmp(line, "File Format=MacCaption_MCC V", 28))
+            continue;
+        if (!strncmp(line, "//", 2))
+            continue;
+        if (!strncmp(line, "Time Code Rate=", 15)) {
+            char *rate_str = line + 15;
+            char *df = NULL;
+            int num = -1, den = -1;
+
+            if (rate_str[0]) {
+                num = strtol(rate_str, &df, 10);
+                den = 1;
+                if (df && !av_strncasecmp(df, "DF", 2)) {
+                    num *= 1000;
+                    den  = 1001;
+                }
+            }
+
+            if (num > 0 && den > 0) {
+                rate = av_make_q(num, den);
+                avpriv_set_pts_info(st, 64, rate.den, rate.num);
+            }
+            continue;
+        }
+
+        if (av_sscanf(line, "%d:%d:%d:%d", &hh, &mm, &ss, &fs) != 4)
+            continue;
+
+        ts = av_rescale(hh * 3600LL + mm * 60LL + ss, rate.num, rate.den) + fs;
+
+        lline = (char *)&line;
+        lline += 12;
+        pos = ff_text_pos(&tr);
+
+        while (lline[i]) {
+            uint8_t v = convert(lline[i]);
+
+            if (v >= 16 && v <= 35) {
+                int idx = v - 16;
+                if (aliases[idx].len) {
+                    if (j >= sizeof(out) - 1 - aliases[idx].len) {
+                        j = 0;
+                        break;
+                    }
+                    memcpy(out + j, aliases[idx].value, aliases[idx].len);
+                    j += aliases[idx].len;
+                }
+            } else {
+                uint8_t vv;
+
+                if (i + 13 >= sizeof(line) - 1)
+                    break;
+                vv = convert(lline[i + 1]);
+                if (j >= sizeof(out) - 1) {
+                    j = 0;
+                    break;
+                }
+                out[j++] = vv | (v << 4);
+                i++;
+            }
+
+            i++;
+        }
+        out[j] = 0;
+
+        if (out[7] & 0x80)
+            start += 4;
+        count = (out[11] & 0x1f) * 3;
+        if (j < start + count + 1)
+            continue;
+
+        if (!count)
+            continue;
+        sub = ff_subtitles_queue_insert(&mcc->q, out + start, count, 0);
+        if (!sub)
+            goto fail;
+
+        sub->pos = pos;
+        sub->pts = ts;
+        sub->duration = 1;
+    }
+
+    ff_subtitles_queue_finalize(s, &mcc->q);
+
+    return ret;
+fail:
+    ff_subtitles_queue_clean(&mcc->q);
+    return AVERROR(ENOMEM);
+}
+
+static int mcc_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    MCCContext *mcc = s->priv_data;
+    return ff_subtitles_queue_read_packet(&mcc->q, pkt);
+}
+
+static int mcc_read_seek(AVFormatContext *s, int stream_index,
+                         int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
+{
+    MCCContext *mcc = s->priv_data;
+    return ff_subtitles_queue_seek(&mcc->q, s, stream_index,
+                                   min_ts, ts, max_ts, flags);
+}
+
+static int mcc_read_close(AVFormatContext *s)
+{
+    MCCContext *mcc = s->priv_data;
+    ff_subtitles_queue_clean(&mcc->q);
+    return 0;
+}
+
+AVInputFormat ff_mcc_demuxer = {
+    .name           = "mcc",
+    .long_name      = NULL_IF_CONFIG_SMALL("MacCaption"),
+    .priv_data_size = sizeof(MCCContext),
+    .read_probe     = mcc_probe,
+    .read_header    = mcc_read_header,
+    .read_packet    = mcc_read_packet,
+    .read_seek2     = mcc_read_seek,
+    .read_close     = mcc_read_close,
+    .extensions     = "mcc",
+};