fix: CEA-708 segmentation faults on MP4 files (#1729)

* fix: CEA-708 segmentation faults on MP4 files

* chore: fix clippy errors

Author: hrideshmg

docs/CHANGES.TXT

@@ -1,5 +1,6 @@
 1.0 (to be released)
 -----------------
+- Fix: Segmentation faults on MP4 files with CEA-708 captions
 - Refactor: Remove API structures from ccextractor
 - New: Add Encoder Module to Rust
 - Fix: Elementary stream regressions

src/lib_ccx/mp4.c

@@ -416,8 +416,6 @@ static int process_clcp(struct lib_ccx_ctx *ctx, struct encoder_ctx *enc_ctx,
 					dbg_print(CCX_DMT_PARSE, "MP4-708: atom skipped (cc_type < 2)\n");
 					continue;
 				}
-				// WARN: otherwise cea-708 will not work
-				dec_ctx->dtvcc->encoder = (void *)enc_ctx;
 				dtvcc_process_data(dec_ctx->dtvcc, (unsigned char *)temp);
 				cb_708++;
 			}
@@ -552,6 +550,9 @@ int processmp4(struct lib_ccx_ctx *ctx, struct ccx_s_mp4Cfg *cfg, char *file)
 	if (enc_ctx)
 		enc_ctx->timing = dec_ctx->timing;
 
+	// WARN: otherwise cea-708 will not work
+	dec_ctx->dtvcc->encoder = (void *)enc_ctx;
+
 	memset(&dec_sub, 0, sizeof(dec_sub));
 	mprint("Opening \'%s\': ", file);
 #ifdef MP4_DEBUG

src/rust/lib_ccxr/src/encoder/txt_helpers.rs

@@ -282,10 +282,10 @@ pub fn get_str_basic(
         info!("WARNING: Encoding is not yet supported\n");
         out_buffer.clear();
         out_buffer.push(0);
-        return 0;
+        0
     } else {
         out_buffer.push(0);
-        return len;
+        len
     }
 }