[FEAT] Port SRT encoder to Rust by DhanushVarma-2 · Pull Request #2227 · CCExtractor/ccextractor

DhanushVarma-2 · 2026-03-24T07:35:36Z

Ported all 5 functions from ccx_encoders_srt.c to Rust:

write_stringz_as_srt → ccxr_write_stringz_as_srt (text subtitles)
write_cc_buffer_as_srt → ccxr_write_cc_buffer_as_srt (CEA-608 with autodash)
write_cc_subtitle_as_srt → ccxr_write_cc_subtitle_as_srt (subtitle chain + teletext multi-page)
write_cc_bitmap_as_srt → ccxr_write_cc_bitmap_as_srt (OCR, behind hardsubx_ocr feature)
write_stringz_as_srt_to_output (internal helper)

Rust is called by default. C fallback behind #ifdef DISABLE_RUST.

Tested on Matroska test files (Elephant Dreams) with 8 subtitle tracks
including English and Hungarian with UTF-8 accented characters.
All extract correctly.

DhanushVarma-2 · 2026-03-25T15:48:15Z

Output

DhanushVarma-2 · 2026-03-26T11:10:56Z

The bitmap function can't be wired right now. CMake sets ENABLE_HARDSUBX for C code but never calls corrosion_set_features to pass hardsubx_ocr to the Rust crate. So the Rust function doesn't get compiled in hardsubx builds, and wiring it from C causes a linker error....that's what happened when the OCR Docker CI failed earlier.

The Rust code is there and ready. To actually wire it, someone needs to add corrosion_set_features(ccx_rust hardsubx_ocr) inside the WITH_HARDSUBX block in CMakeLists.txt. I'll do that as a follow-up PR to keep this one clean.

And yes get_teletext_output and get_teletext_srt_counter both exist in ccx_encoders_common.c (lines 1356 and 1460)
They've been there since the teletext multi-page feature was added.

ccextractor-bot · 2026-03-26T11:36:33Z

CCExtractor CI platform finished running the test files on linux. Below is a summary of the test results, when compared to test for commit 03ad9e8...:

Report Name	Tests Passed
Broken	10/13
CEA-708	1/14
DVB	4/7
DVD	3/3
DVR-MS	2/2
General	27/27
Hardsubx	1/1
Hauppage	3/3
MP4	3/3
NoCC	10/10
Options	79/86
Teletext	20/21
WTV	13/13
XDS	34/34

Your PR breaks these cases:

ccextractor --startcreditsnotafter 2 --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9...
ccextractor --startcreditsforatmost 2 --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9...

NOTE: The following tests have been failing on the master branch as well as the PR:

ccextractor --out=srt --latin1 --autoprogram 73d9313d64..., Last passed:
Test 8738
ccextractor --out=ttxt --latin1 001dd8cdf7..., Last passed:
Test 8738
ccextractor --out=srt --latin1 4d4e938ef6..., Last passed:
Test 8738
ccextractor --service 1 --out=txt --no-bom --no-rollup ea83ff7bcb..., Last passed:
Test 8738
ccextractor --service 1 --out=txt f17524b53f..., Last passed:
Test 8738
ccextractor --service 1 --out=txt 80848c45f8..., Last passed:
Test 8738
ccextractor --service 1 --out=txt --no-bom --no-rollup b5d6aad89f..., Last passed:
Test 8738
ccextractor --service 1[EUC-KR] --out=txt --no-rollup b5d6aad89f..., Last passed:
Test 8738
ccextractor --service 1 --out=srt da904de35d..., Last passed:
Test 8738
ccextractor --service 1 --out=sami da904de35d..., Last passed:
Test 8738
ccextractor --service 1 --out=ttxt da904de35d..., Last passed:
Test 8926
ccextractor --service 1[EUC-KR] b5d6aad89f..., Last passed:
Test 8738
ccextractor --service 1[EUC-KR] --no-rollup b5d6aad89f..., Last passed:
Test 8738
ccextractor --service all da904de35d..., Last passed:
Test 8738
ccextractor --service all[EUC-KR] b5d6aad89f..., Last passed:
Test 8738
ccextractor --service 1,2[UTF-8],3[EUC-KR],54 --out=txt da904de35d..., Last passed:
Test 8738
ccextractor --autoprogram --out=srt --latin1 d41b53b504..., Last passed:
Test 8738
ccextractor --stdout --quiet --no-fontcolor 79a51f3500..., Last passed:
Test 8738
ccextractor --stdout --quiet --no-fontcolor 767b546f96..., Last passed:
Test 8738
ccextractor --service 1 c83f765c66..., Last passed:
Test 8738
ccextractor --myth c83f765c66..., Last passed:
Test 8738
ccextractor --in=raw fb79021542..., Last passed:
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ccextractor --mp4vidtrack 5df914ce77..., Last passed:
Test 8738
ccextractor --xmltv=3 --out=null 96efd279cf..., Last passed:
Test 8738
ccextractor --datapid 2310 --autoprogram --out=srt --latin1 e639e54550..., Last passed:
Test 8738

Congratulations: Merging this PR would fix the following tests:

ccextractor --autoprogram --out=ttxt --latin1 --ucla --xds 8e8229b88b..., Last passed: Never
ccextractor --autoprogram --out=srt --latin1 --quant 0 85271be4d2..., Last passed: Never
ccextractor --autoprogram --out=ttxt --latin1 132d7df7e9..., Last passed: Never
ccextractor --autoprogram --out=ttxt --latin1 99e5eaafdc..., Last passed: Never
ccextractor --autoprogram --out=srt --latin1 b22260d065..., Last passed: Never
ccextractor --autoprogram --out=ttxt --latin1 --ucla 7aad20907e..., Last passed: Never
ccextractor --autoprogram --out=ttxt --latin1 --ucla dab1c1bd65..., Last passed: Never
ccextractor --autoprogram --out=ttxt --latin1 01509e4d27..., Last passed: Never
ccextractor --out=srt --latin1 --autoprogram 29e5ffd34b..., Last passed: Never
ccextractor --out=spupng c83f765c66..., Last passed: Never
ccextractor --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9..., Last passed: Never
ccextractor --startcreditsnotbefore 1 --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9..., Last passed: Never
ccextractor --startcreditsforatleast 1 --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9..., Last passed: Never
ccextractor --autoprogram --out=ttxt --xds --latin1 --ucla 85058ad37e..., Last passed: Never
ccextractor --autoprogram --out=srt --latin1 --ucla b22260d065..., Last passed: Never
ccextractor --autoprogram --out=ttxt --latin1 --ucla --xds 7f41299cc7..., Last passed: Never

It seems that not all tests were passed completely. This is an indication that the output of some files is not as expected (but might be according to you).

Check the result page for more info.

steel-bucket

Compare Master Branch SP test results and yours

steel-bucket · 2026-03-26T21:32:23Z

src/lib_ccx/ccx_encoders_srt.c

+#ifndef DISABLE_RUST
+extern int ccxr_write_stringz_as_srt(const char *string, struct encoder_ctx *context, LLONG ms_start, LLONG ms_end);
+extern int ccxr_write_cc_buffer_as_srt(struct eia608_screen *data, struct encoder_ctx *context);


DISABLE_RUST is deprecated

steel-bucket · 2026-03-26T21:36:52Z

src/rust/src/encoder/srt.rs

+extern "C" {
+    fn get_decoder_line_encoded(
+        ctx: *mut encoder_ctx,
+        buffer: *mut c_uchar,
+        line_num: c_int,
+        data: *const eia608_screen,
+    ) -> c_uint;
+}
+


Import Externs from the way we do in src/rust/src/lib.rs, not this way

ccextractor-bot · 2026-03-27T09:31:38Z

CCExtractor CI platform finished running the test files on windows. Below is a summary of the test results, when compared to test for commit 74e3842...:

Report Name	Tests Passed
Broken	9/13
CEA-708	1/14
DVB	4/7
DVD	3/3
DVR-MS	2/2
General	22/27
Hardsubx	1/1
Hauppage	3/3
MP4	3/3
NoCC	10/10
Options	81/86
Teletext	20/21
WTV	13/13
XDS	31/34

Your PR breaks these cases:

ccextractor --autoprogram --out=ttxt --latin1 --ucla --xds 8e8229b88b...
ccextractor --autoprogram --out=ttxt --latin1 132d7df7e9...
ccextractor --autoprogram --out=ttxt --latin1 99e5eaafdc...
ccextractor --autoprogram --out=srt --latin1 b22260d065...
ccextractor --autoprogram --out=ttxt --latin1 --ucla 7aad20907e...
ccextractor --autoprogram --out=ttxt --latin1 01509e4d27...
ccextractor --autoprogram --out=ttxt --xds --latin1 --ucla 85058ad37e...
ccextractor --autoprogram --out=srt --latin1 --ucla b22260d065...
ccextractor --autoprogram --out=ttxt --latin1 --ucla --xds 7f41299cc7...

NOTE: The following tests have been failing on the master branch as well as the PR:

ccextractor --out=srt --latin1 --autoprogram 73d9313d64..., Last passed:
Test 8611
ccextractor --out=ttxt --latin1 001dd8cdf7..., Last passed:
Test 8611
ccextractor --out=srt --latin1 4d4e938ef6..., Last passed:
Test 8611
ccextractor --service 1 --out=txt --no-bom --no-rollup ea83ff7bcb..., Last passed:
Test 8611
ccextractor --service 1 --out=txt f17524b53f..., Last passed:
Test 8611
ccextractor --service 1 --out=txt 80848c45f8..., Last passed:
Test 8611
ccextractor --service 1 --out=txt --no-bom --no-rollup b5d6aad89f..., Last passed:
Test 8611
ccextractor --service 1[EUC-KR] --out=txt --no-rollup b5d6aad89f..., Last passed:
Test 8611
ccextractor --service 1 --out=srt da904de35d..., Last passed:
Test 8611
ccextractor --service 1 --out=sami da904de35d..., Last passed:
Test 8611
ccextractor --service 1 --out=ttxt da904de35d..., Last passed:
Test 8943
ccextractor --service 1[EUC-KR] b5d6aad89f..., Last passed:
Test 8611
ccextractor --service 1[EUC-KR] --no-rollup b5d6aad89f..., Last passed:
Test 8611
ccextractor --service all da904de35d..., Last passed:
Test 8611
ccextractor --service all[EUC-KR] b5d6aad89f..., Last passed:
Test 8611
ccextractor --service 1,2[UTF-8],3[EUC-KR],54 --out=txt da904de35d..., Last passed:
Test 8611
ccextractor --autoprogram --out=srt --latin1 d41b53b504..., Last passed:
Test 8611
ccextractor --stdout --quiet --no-fontcolor 79a51f3500..., Last passed:
Test 8611
ccextractor --stdout --quiet --no-fontcolor 767b546f96..., Last passed:
Test 8611
ccextractor --service 1 c83f765c66..., Last passed:
Test 8611
ccextractor --myth c83f765c66..., Last passed:
Test 8611
ccextractor --in=raw fb79021542..., Last passed:
Test 8611
ccextractor --mp4vidtrack 5df914ce77..., Last passed:
Test 8611
ccextractor --xmltv=3 --out=null 96efd279cf..., Last passed:
Test 8611
ccextractor --datapid 2310 --autoprogram --out=srt --latin1 e639e54550..., Last passed:
Test 8611

Congratulations: Merging this PR would fix the following tests:

ccextractor --autoprogram --out=srt --latin1 --quant 0 85271be4d2..., Last passed: Never
ccextractor --autoprogram --out=ttxt --latin1 --ucla dab1c1bd65..., Last passed: Never
ccextractor --out=srt --latin1 --autoprogram 29e5ffd34b..., Last passed: Never
ccextractor --out=spupng c83f765c66..., Last passed: Never
ccextractor --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9..., Last passed: Never
ccextractor --startcreditsnotbefore 1 --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9..., Last passed: Never
ccextractor --startcreditsnotafter 2 --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9..., Last passed: Never
ccextractor --startcreditsforatleast 1 --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9..., Last passed: Never
ccextractor --startcreditsforatmost 2 --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9..., Last passed: Never

It seems that not all tests were passed completely. This is an indication that the output of some files is not as expected (but might be according to you).

Check the result page for more info.

Implement ccxr_write_stringz_as_srt and ccxr_write_cc_buffer_as_srt in src/rust/src/encoder/srt.rs. Covers: - Subtitle counter and timestamp formatting with -1ms overlap prevention - \n unescape handling for multi-line subtitles - Encoding conversion (UTF-8, Latin1, UCS-2) - Autodash detection for CEA-608 screen buffers - Speaker name detection (colon-based) Uses existing Rust encoder infrastructure (encode_line, write_wrapped) and calls C get_decoder_line_encoded for CEA-608 line encoding until that function is also ported. Exported as #[no_mangle] extern C functions ready to replace the C versions in ccx_encoders_srt.c.

DhanushVarma-2 force-pushed the feat/srt-encoder-rust branch 7 times, most recently from d9b3a3a to c6523ce Compare March 25, 2026 11:07

DhanushVarma-2 force-pushed the feat/srt-encoder-rust branch 5 times, most recently from af58374 to a1dc78a Compare March 26, 2026 11:07

steel-bucket reviewed Mar 26, 2026

View reviewed changes

DhanushVarma-2 force-pushed the feat/srt-encoder-rust branch from a1dc78a to 43ef45f Compare March 27, 2026 08:34

DhanushVarma-2 force-pushed the feat/srt-encoder-rust branch from 43ef45f to 043901b Compare March 28, 2026 09:40

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[FEAT] Port SRT encoder to Rust#2227

[FEAT] Port SRT encoder to Rust#2227
DhanushVarma-2 wants to merge 1 commit intoCCExtractor:masterfrom
DhanushVarma-2:feat/srt-encoder-rust

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