FFprobe closed_captions JSON tag not set

[ptr727]

ffprobe does not identify closed captions when using JSON output mode.

Unformatted output:

./ffprobe.exe D:\Temp\CC.mkv
  Stream #0:0(eng): Video: h264 (High), yuv420p(tv, bt709, progressive), 1920x1080, Closed Captions, SAR 1:1 DAR 16:9, 29.97 fps, 29.97 tbr, 1k tbn (default)

Note the Closed Captions attribute.

JSON output:

./ffprobe.exe -loglevel quiet -print_format json -show_streams -show_format D:\Temp\CC.mkv
{
    "streams": [
        {
            "index": 0,
            "codec_name": "h264",
            "codec_long_name": "H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10",
...
            "closed_captions": 0,

Note the closed_captions attribute is 0, expect it to be 1.

Asked for help or alternatives here: https://www.reddit.com/r/ffmpeg/comments/tcnhto/how_to_detect_closed_captions_in_video_stream/ https://forum.videohelp.com/threads/405123-Detect-embedded-closed-captions-in-video-stream-using-ffprobe-json-output

Discovered an abandoned patch for exactly this issue, seems there was some internal disagreement: https://patchwork.ffmpeg.org/project/ffmpeg/patch/MN2PR04MB59815313285AA685E37D09AEBAB09@MN2PR04MB5981.namprd04.prod.outlook.com/ https://patchwork.ffmpeg.org/project/ffmpeg/list/?series=&submitter=&state=*&q=closed_captions&archive=both&delegate= https://www.mail-archive.com/[email protected]/msg126211.html

diff --git a/fftools/ffprobe.c b/fftools/ffprobe.c
index 90e895bbf9..f5c6335a13 100644
--- a/fftools/ffprobe.c
+++ b/fftools/ffprobe.c
@@ -2655,9 +2655,9 @@  static int show_stream(WriterContext *w, AVFormatContext *fmt_ctx, int stream_id
         if (dec_ctx) {
             print_int("coded_width",  dec_ctx->coded_width);
             print_int("coded_height", dec_ctx->coded_height);
-            print_int("closed_captions", !!(dec_ctx->properties & FF_CODEC_PROPERTY_CLOSED_CAPTIONS));
-            print_int("film_grain", !!(dec_ctx->properties & FF_CODEC_PROPERTY_FILM_GRAIN));
         }
+        print_int("closed_captions", !!(par->properties & FF_CODEC_PROPERTY_CLOSED_CAPTIONS));
+        print_int("film_grain", !!(par->properties & FF_CODEC_PROPERTY_FILM_GRAIN));
         print_int("has_b_frames", par->video_delay);
         sar = av_guess_sample_aspect_ratio(fmt_ctx, stream, NULL);
         if (sar.num) {

Source related to closed_captions setting: https://github.com/FFmpeg/FFmpeg/blob/b8e58f0858116ac102fc116ce1bdf6727df1eb0c/libavcodec/avcodec.c#L650 https://github.com/FFmpeg/FFmpeg/blob/316e0ff752c782439843cc63d0eb8b9c998e47de/fftools/ffprobe.c#L2902

My request to the ffmpeg-devel list to reconsider: https://www.mail-archive.com/[email protected]/msg133559.html