feat(input): Add native SCC (Scenarist Closed Caption) input support

Author: cfsmp3

src/ccextractor.c

@@ -202,6 +202,12 @@ int start_ccx()
 				if (!ret)
 					ret = tmp;
 				break;
+			case CCX_SM_SCC:
+				mprint("\rAnalyzing data in SCC (Scenarist Closed Caption) mode\n");
+				tmp = raw_loop(ctx);
+				if (!ret)
+					ret = tmp;
+				break;
 			case CCX_SM_RCWT:
 				mprint("\rAnalyzing data in CCExtractor's binary format\n");
 				tmp = rcwt_loop(ctx);

src/lib_ccx/ccx_common_constants.h

@@ -212,6 +212,7 @@ enum ccx_stream_mode_enum
 	CCX_SM_GXF = 11,
 	CCX_SM_MKV = 12,
 	CCX_SM_MXF = 13,
+	CCX_SM_SCC = 14, // Scenarist Closed Caption input
 
 	CCX_SM_AUTODETECT = 16
 };

src/lib_ccx/ccx_common_option.c

@@ -152,6 +152,8 @@ void init_options(struct ccx_s_options *options)
 	    options->settings_dtvcc.services_enabled, 0,
 	    CCX_DTVCC_MAX_SERVICES * sizeof(options->settings_dtvcc.services_enabled[0]));
 
+	options->scc_framerate = 0; // Default: 29.97fps
+
 #ifdef WITH_LIBCURL
 	options->curlposturl = NULL;
 #endif

src/lib_ccx/ccx_common_option.h

@@ -195,6 +195,7 @@ struct ccx_s_options // Options from user parameters
 	int multiprogram;
 	int out_interval;
 	int segment_on_key_frames_only;
+	int scc_framerate; // SCC input framerate: 0=29.97 (default), 1=24, 2=25, 3=30
 #ifdef WITH_LIBCURL
 	char *curlposturl;
 #endif

src/lib_ccx/general_loop.c

@@ -575,6 +575,7 @@ int raw_loop(struct lib_ccx_ctx *ctx)
 	struct lib_cc_decode *dec_ctx = NULL;
 	int caps = 0;
 	int is_dvdraw = 0;     // Flag to track if this is DVD raw format
+	int is_scc = 0;	       // Flag to track if this is SCC format
 	int is_mcc_output = 0; // Flag for MCC output format
 
 	dec_ctx = update_decoder_list(ctx);
@@ -607,13 +608,20 @@ int raw_loop(struct lib_ccx_ctx *ctx)
 			break;
 
 		// Check if this is DVD raw format using Rust detection
-		if (!is_dvdraw && ccxr_is_dvdraw_header(data->buffer, (unsigned int)data->len))
+		if (!is_dvdraw && !is_scc && ccxr_is_dvdraw_header(data->buffer, (unsigned int)data->len))
 		{
 			is_dvdraw = 1;
 			mprint("Detected McPoodle's DVD raw format\n");
 		}
 
-		if (is_mcc_output && !is_dvdraw)
+		// Check if this is SCC format using Rust detection
+		if (!is_scc && !is_dvdraw && ccxr_is_scc_file(data->buffer, (unsigned int)data->len))
+		{
+			is_scc = 1;
+			mprint("Detected SCC (Scenarist Closed Caption) format\n");
+		}
+
+		if (is_mcc_output && !is_dvdraw && !is_scc)
 		{
 			// For MCC output, encode raw data directly without decoding
 			// This preserves the original CEA-608 byte pairs in CDP format
@@ -626,6 +634,11 @@ int raw_loop(struct lib_ccx_ctx *ctx)
 			// Use Rust implementation - handles timing internally
 			ret = ccxr_process_dvdraw(dec_ctx, dec_sub, data->buffer, (unsigned int)data->len);
 		}
+		else if (is_scc)
+		{
+			// Use Rust SCC implementation - handles timing internally via SMPTE timecodes
+			ret = ccxr_process_scc(dec_ctx, dec_sub, data->buffer, (unsigned int)data->len, ccx_options.scc_framerate);
+		}
 		else
 		{
 			ret = process_raw(dec_ctx, dec_sub, data->buffer, data->len);

src/lib_ccx/lib_ccx.h

@@ -43,7 +43,7 @@ struct file_report
 };
 
 // Stuff for telxcc.c
-#define MAX_TLT_PAGES_EXTRACT 8  // Maximum number of teletext pages to extract simultaneously
+#define MAX_TLT_PAGES_EXTRACT 8 // Maximum number of teletext pages to extract simultaneously
 
 struct ccx_s_teletext_config
 {
@@ -55,11 +55,11 @@ struct ccx_s_teletext_config
 	uint8_t nonempty : 1; // produce at least one (dummy) frame
 	// uint8_t se_mode : 1;                                    // search engine compatible mode => Uses CCExtractor's write_format
 	// uint64_t utc_refvalue;                                  // UTC referential value => Moved to ccx_decoders_common, so can be used for other decoders (608/xds) too
-	uint16_t user_page;					   // Page selected by user (legacy, first page)
+	uint16_t user_page; // Page selected by user (legacy, first page)
 	// Multi-page teletext extraction (issue #665)
-	uint16_t user_pages[MAX_TLT_PAGES_EXTRACT];  // Pages selected by user for extraction
-	int num_user_pages;                          // Number of pages to extract (0 = auto-detect single page)
-	int extract_all_pages;                       // If 1, extract all detected subtitle pages
+	uint16_t user_pages[MAX_TLT_PAGES_EXTRACT];		   // Pages selected by user for extraction
+	int num_user_pages;					   // Number of pages to extract (0 = auto-detect single page)
+	int extract_all_pages;					   // If 1, extract all detected subtitle pages
 	int dolevdist;						   // 0=Don't attempt to correct errors
 	int levdistmincnt, levdistmaxpct;			   // Means 2 fails or less is "the same", 10% or less is also "the same"
 	struct ccx_boundary_time extraction_start, extraction_end; // Segment we actually process
@@ -183,6 +183,10 @@ size_t process_raw(struct lib_cc_decode *ctx, struct cc_subtitle *sub, unsigned
 unsigned int ccxr_process_dvdraw(struct lib_cc_decode *ctx, struct cc_subtitle *sub, const unsigned char *buffer, unsigned int len);
 int ccxr_is_dvdraw_header(const unsigned char *buffer, unsigned int len);
 
+// Rust FFI: SCC (Scenarist Closed Caption) format processing (see src/rust/src/demuxer/scc.rs)
+unsigned int ccxr_process_scc(struct lib_cc_decode *ctx, struct cc_subtitle *sub, const unsigned char *buffer, unsigned int len, int framerate);
+int ccxr_is_scc_file(const unsigned char *buffer, unsigned int len);
+
 int general_loop(struct lib_ccx_ctx *ctx);
 void process_hex(struct lib_ccx_ctx *ctx, char *filename);
 int rcwt_loop(struct lib_ccx_ctx *ctx);

src/lib_ccx/stream_functions.c

@@ -78,6 +78,30 @@ void detect_stream_type(struct ccx_demuxer *ctx)
 		    ctx->startbytes[7] == 0xf8)
 			ctx->stream_mode = CCX_SM_MCPOODLESRAW;
 	}
+	// Check for SCC (Scenarist Closed Caption) text format
+	// SCC files start with "Scenarist_SCC V1.0" (18 bytes), optionally with UTF-8 BOM (3 bytes)
+	if (ctx->stream_mode == CCX_SM_ELEMENTARY_OR_NOT_FOUND)
+	{
+		unsigned char *check_buf = ctx->startbytes;
+		int check_pos = 0;
+
+		// Skip UTF-8 BOM if present
+		if (ctx->startbytes_avail >= 3 &&
+		    ctx->startbytes[0] == 0xEF &&
+		    ctx->startbytes[1] == 0xBB &&
+		    ctx->startbytes[2] == 0xBF)
+		{
+			check_buf += 3;
+			check_pos = 3;
+		}
+
+		if (ctx->startbytes_avail >= check_pos + 18 &&
+		    memcmp(check_buf, "Scenarist_SCC V1.0", 18) == 0)
+		{
+			ctx->stream_mode = CCX_SM_SCC;
+			mprint("Detected SCC (Scenarist Closed Caption) format\n");
+		}
+	}
 #ifdef WTV_DEBUG
 	if (ctx->stream_mode == CCX_SM_ELEMENTARY_OR_NOT_FOUND && ctx->startbytes_avail >= 6)
 	{

src/rust/lib_ccxr/src/common/constants.rs

@@ -278,6 +278,7 @@ pub enum StreamMode {
     Gxf = 11,
     Mkv = 12,
     Mxf = 13,
+    Scc = 14, // Scenarist Closed Caption input
     Autodetect = 16,
 }
 #[derive(Debug, Eq, Clone, Copy)]

src/rust/lib_ccxr/src/common/options.rs

@@ -517,6 +517,8 @@ pub struct Options {
     pub multiprogram: bool,
     pub out_interval: i32,
     pub segment_on_key_frames_only: bool,
+    /// SCC input framerate: 0=29.97 (default), 1=24, 2=25, 3=30
+    pub scc_framerate: i32,
     pub debug_mask: DebugMessageMask,
 
     #[cfg(feature = "with_libcurl")]
@@ -618,6 +620,7 @@ impl Default for Options {
             multiprogram: Default::default(),
             out_interval: -1,
             segment_on_key_frames_only: Default::default(),
+            scc_framerate: 0, // 0 = 29.97fps (default)
             debug_mask: DebugMessageMask::new(
                 DebugMessageFlag::GENERIC_NOTICE,
                 DebugMessageFlag::VERBOSE,

src/rust/src/args.rs

@@ -290,6 +290,11 @@ pub struct Args {
     /// DVD Recorder)
     #[arg(long="90090", verbatim_doc_comment, help_heading=OPTIONS_AFFECTING_INPUT_FILES)]
     pub mpeg90090: bool,
+    /// Set the frame rate for SCC (Scenarist Closed Caption) input files.
+    /// Valid values: 29.97 (default), 24, 25, 30
+    /// Example: --scc-framerate 25
+    #[arg(long="scc-framerate", verbatim_doc_comment, value_name="fps", help_heading=OPTIONS_AFFECTING_INPUT_FILES)]
+    pub scc_framerate: Option<String>,
     /// By default, ccextractor will process input files in
     /// sequence as if they were all one large file (i.e.
     /// split by a generic, non video-aware tool. If you