avformat: add SCC muxer

Signed-off-by: Paul B Mahol <onemda@gmail.com>

Changelog

@@ -18,6 +18,7 @@ version <next>:
 - readeia608 filter
 - Sample Dump eXchange demuxer
 - abitscope multimedia filter
+- Scenarist Closed Captions demuxer and muxer
 
 version 3.2:
 - libopenmpt demuxer

libavformat/Makefile

@@ -435,6 +435,7 @@ OBJS-$(CONFIG_SAP_DEMUXER)               += sapdec.o
 OBJS-$(CONFIG_SAP_MUXER)                 += sapenc.o
 OBJS-$(CONFIG_SBG_DEMUXER)               += sbgdec.o
 OBJS-$(CONFIG_SCC_DEMUXER)               += sccdec.o subtitles.o
+OBJS-$(CONFIG_SCC_MUXER)                 += sccenc.o subtitles.o
 OBJS-$(CONFIG_SDP_DEMUXER)               += rtsp.o
 OBJS-$(CONFIG_SDR2_DEMUXER)              += sdr2.o
 OBJS-$(CONFIG_SDS_DEMUXER)               += sdsdec.o

libavformat/allformats.c

@@ -273,7 +273,7 @@ void av_register_all(void)
     REGISTER_DEMUXER (SAMI,             sami);
     REGISTER_MUXDEMUX(SAP,              sap);
     REGISTER_DEMUXER (SBG,              sbg);
-    REGISTER_DEMUXER (SCC,              scc);
+    REGISTER_MUXDEMUX(SCC,              scc);
     REGISTER_DEMUXER (SDP,              sdp);
     REGISTER_DEMUXER (SDR2,             sdr2);
     REGISTER_DEMUXER (SDS,              sds);

libavformat/sccenc.c

@@ -0,0 +1,123 @@
+/*
+ * SCC muxer
+ * Copyright (c) 2017 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 "libavutil/log.h"
+#include "libavutil/intreadwrite.h"
+
+typedef struct SCCContext {
+    int prev_h, prev_m, prev_s, prev_f;
+    int inside;
+    int n;
+} SCCContext;
+
+static int scc_write_header(AVFormatContext *avf)
+{
+    SCCContext *scc = avf->priv_data;
+
+    if (avf->nb_streams != 1 ||
+        avf->streams[0]->codecpar->codec_type != AVMEDIA_TYPE_SUBTITLE) {
+        av_log(avf, AV_LOG_ERROR,
+               "SCC supports only a single subtitles stream.\n");
+        return AVERROR(EINVAL);
+    }
+    if (avf->streams[0]->codecpar->codec_id != AV_CODEC_ID_EIA_608) {
+        av_log(avf, AV_LOG_ERROR,
+               "Unsupported subtitles codec: %s\n",
+               avcodec_get_name(avf->streams[0]->codecpar->codec_id));
+        return AVERROR(EINVAL);
+    }
+    avpriv_set_pts_info(avf->streams[0], 64, 1, 1000);
+    avio_printf(avf->pb, "Scenarist_SCC V1.0\n");
+
+    scc->prev_h = scc->prev_m = scc->prev_s = scc->prev_f = -1;
+    scc->inside = 0;
+
+    return 0;
+}
+
+static int scc_write_packet(AVFormatContext *avf, AVPacket *pkt)
+{
+    SCCContext *scc = avf->priv_data;
+    int64_t pts = pkt->pts;
+    int i, h, m, s, f;
+
+    if (pts == AV_NOPTS_VALUE) {
+        av_log(avf, AV_LOG_WARNING,
+               "Insufficient timestamps.\n");
+        return 0;
+    }
+
+    h = (int)(pts / (3600000));
+    m = (int)(pts / (60000)) % 60;
+    s = (int)(pts /  1000) % 60;
+    f = (int)(pts %  1000) / 33;
+
+    for (i = 0; i < pkt->size; i+=3) {
+        if (pkt->data[i] == 0xfc && ((pkt->data[i + 1] != 0x80 || pkt->data[i + 2] != 0x80)))
+            break;
+    }
+    if (i >= pkt->size)
+        return 0;
+
+    if (!scc->inside && (scc->prev_h != h || scc->prev_m != m || scc->prev_s != s || scc->prev_f != f)) {
+        avio_printf(avf->pb, "\n%02d:%02d:%02d:%02d\t", h, m, s, f);
+        scc->inside = 1;
+    }
+    for (i = 0; i < pkt->size; i+=3) {
+        if (i + 3 > pkt->size)
+            break;
+
+        if (pkt->data[i] != 0xfc || (pkt->data[i + 1] == 0x80 && pkt->data[i + 2] == 0x80))
+            continue;
+        if (!scc->inside) {
+            avio_printf(avf->pb, "\n%02d:%02d:%02d:%02d\t", h, m, s, f);
+            scc->inside = 1;
+        }
+        if (scc->n > 0)
+            avio_printf(avf->pb, " ");
+        avio_printf(avf->pb, "%02x%02x", pkt->data[i + 1], pkt->data[i + 2]);
+        scc->n++;
+    }
+    if (scc->inside && (scc->prev_h != h || scc->prev_m != m || scc->prev_s != s || scc->prev_f != f)) {
+        avio_printf(avf->pb, "\n");
+        scc->n = 0;
+        scc->inside = 0;
+    }
+
+    scc->prev_h = h;
+    scc->prev_m = m;
+    scc->prev_s = s;
+    scc->prev_f = f;
+    return 0;
+}
+
+AVOutputFormat ff_scc_muxer = {
+    .name           = "scc",
+    .long_name      = NULL_IF_CONFIG_SMALL("Scenarist Closed Captions"),
+    .extensions     = "scc",
+    .priv_data_size = sizeof(SCCContext),
+    .write_header   = scc_write_header,
+    .write_packet   = scc_write_packet,
+    .flags          = AVFMT_GLOBALHEADER | AVFMT_VARIABLE_FPS | AVFMT_TS_NONSTRICT,
+    .subtitle_codec = AV_CODEC_ID_EIA_608,
+};

libavformat/version.h

@@ -32,7 +32,7 @@
 // Major bumping may affect Ticket5467, 5421, 5451(compatibility with Chromium)
 // Also please add any ticket numbers that you believe might be affected here
 #define LIBAVFORMAT_VERSION_MAJOR  57
-#define LIBAVFORMAT_VERSION_MINOR  65
+#define LIBAVFORMAT_VERSION_MINOR  66
 #define LIBAVFORMAT_VERSION_MICRO 100
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \