feat: Add --input scc option for SCC input format

Add support for `--input scc` command line option to explicitly specify
SCC (Scenarist Closed Caption) input format, for consistency with other
input format options.

Changes:
- Add `Scc` variant to `InFormat` enum in args.rs
- Handle `InFormat::Scc` in parser.rs to set StreamMode::Scc
- Add `StreamMode::Scc` case in print_cfg() in both Rust and C code

Fixes #1972

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/lib_ccx/ccx_demuxer.c

@@ -285,6 +285,9 @@ static void ccx_demuxer_print_cfg(struct ccx_demuxer *ctx)
 		case CCX_SM_MXF:
 			mprint("MXF");
 			break;
+		case CCX_SM_SCC:
+			mprint("SCC");
+			break;
 #ifdef WTV_DEBUG
 		case CCX_SM_HEX_DUMP:
 			mprint("Hex");

src/rust/src/args.rs

@@ -990,6 +990,8 @@ pub enum InFormat {
     Mkv,
     /// Material Exchange Format (MXF).
     Mxf,
+    /// Scenarist Closed Caption (SCC).
+    Scc,
     #[cfg(feature = "wtv_debug")]
     // For WTV Debug mode only
     Hex,

src/rust/src/demuxer/demux.rs

@@ -327,6 +327,9 @@ impl CcxDemuxer<'_> {
             StreamMode::Mxf => {
                 info!("MXF");
             }
+            StreamMode::Scc => {
+                info!("SCC");
+            }
             #[cfg(feature = "wtv_debug")]
             StreamMode::HexDump => {
                 info!("Hex");

src/rust/src/parser.rs

@@ -311,6 +311,7 @@ impl OptionsExt for Options {
             InFormat::Mp4 => self.demux_cfg.auto_stream = StreamMode::Mp4,
             InFormat::Mkv => self.demux_cfg.auto_stream = StreamMode::Mkv,
             InFormat::Mxf => self.demux_cfg.auto_stream = StreamMode::Mxf,
+            InFormat::Scc => self.demux_cfg.auto_stream = StreamMode::Scc,
         }
     }