No captions were found in input

[jaum20]

I am trying to use this to extract emeded subs ib mkv files, but it aways throw an error 'No captions were found in input'. I can successfully extract the subs using mkvextract, but I wanted to test if CCExtractor is faster.

CCExtractor detailed version info
	Version: 0.94
	Git commit: ffe075b1f36c63c93746b78252d857c01722e30b
	Compilation date: 2025-02-21
	CEA-708 decoder: C
	File SHA256: 28d12d901ad2f3b6fa4a4e3507323a1017369c012720bc889ae5be6fecb2bc1c
Libraries used by CCExtractor
	Tesseract Version: 4.1.1
	Leptonica Version: leptonica-1.82.0
	libGPAC Version: 2.0
	zlib: 1.2.11
	utf8proc Version: 2.4.0
	protobuf-c Version: 1.3.1
	libpng Version: 1.6.37
	FreeType 
	libhash
	nuklear
	libzvbi

my system: Linux 6.8.0-52-generic #53~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Wed Jan 15 19:18:46 UTC 2 x86_64 x86_64 x86_64 GNU/Linux

error output:

$ ccextractor input.mkv

CCExtractor 0.94, Carlos Fernandez Sanz, Volker Quetschke.
Teletext portions taken from Petr Kutalek's telxcc
--------------------------------------------------------------------------
Input: input.mkv
[Extract: 1] [Stream mode: Autodetect]
[Program : Auto ] [Hauppage mode: No] [Use MythTV code: Auto]
[CEA-708: 63 decoders active]
[CEA-708: using charset "none" for all services]
[Timing mode: Auto] [Debug: No] [Buffer input: No]
[Use pic_order_cnt_lsb for H.264: No] [Print CC decoder traces: No]
[Target format: .srt] [Encoding: UTF-8] [Delay: 0] [Trim lines: No]
[Add font color data: Yes] [Add font typesetting: Yes]
[Convert case: No][Filter profanity: No] [Video-edit join: No]
[Extraction start time: not set (from start)]
[Extraction end time: not set (to end)]
[Live stream: No] [Clock frequency: 90000]
[Teletext page: Autodetect]
[Start credits text: None]
[Quantisation-mode: CCExtractor's internal function]
[Tesseract PSM: 3]

-----------------------------------------------------------------
Opening file: input.mkv
File seems to be a Matroska/WebM container
Analyzing data in Matroska mode


Document type: matroska
Timecode scale: 1000000
Muxing app: libebml v1.4.5 + libmatroska v1.7.1
Writing app: mkvmerge v88.0 ('Legends') 64-bit

Track entry:
    Track number: 1
    UID: 4282142458775063981
    Type: video
    Language: und
    Codec ID: V_MPEGH/ISO/HEVC

Matroska parser error: Unknown element 0x22b59d83 at position 4507, skipping segment track entry block

Track entry:
    Track number: 2
    UID: 12022521161955789809
    Type: audio
    Language: por
    Codec ID: A_EAC3

Matroska parser error: Unknown element 0x22b59d82 at position 4580, skipping segment track entry block

Track entry:
    Track number: 3
    UID: 15504365667180735517
    Type: audio
    Codec ID: A_EAC3

Matroska parser error: Unknown element 0x22b59d82 at position 4647, skipping segment track entry block

Track entry:
    Track number: 4
    UID: 13749157252674005858
    Type: subtitle
    Language: por
    Codec ID: S_TEXT/UTF8

Matroska parser error: Unknown element 0x22b59d82 at position 4713, skipping segment track entry block

Track entry:
    Track number: 5
    UID: 14720255758613299147
    Type: subtitle
    Language: por
    Codec ID: S_TEXT/UTF8

Matroska parser error: Unknown element 0x22b59d82 at position 4785, skipping segment track entry block

Track entry:
    Track number: 6
    UID: 13367189494955818437
    Type: subtitle
    Language: por
    Codec ID: S_TEXT/UTF8

Matroska parser error: Unknown element 0x22b59d82 at position 4836, skipping segment track entry block
 99%  |  00:00
100%  |  00:00

Found no AVC track. 

Total frames time:	  00:00:00:000  (0 frames at 29.97fps)
Done, processing time = 0 seconds

No captions were found in input.
Issues? Open a ticket here
https://github.com/CCExtractor/ccextractor/issues

[tank0nf]

Hey @jaum20,
We sincerely apologize for the inconvenience you're experiencing.

Could you kindly provide the video file in question via a link? This will allow us to replicate the issue and work towards a solution as quickly as possible.

Thank you for your understanding and cooperation.
Tank0nf.

[jaum20]

I will share a sample of it, but I have found this issue with every video I have tested

[jaum20]

link to sample: https://limewire.com/d/d05cae7c-0cdc-48b8-b07f-f18c5d61f8a2#lTi0BfIZtX84qvg3DMvrlQXjrkglm7IPTVlIc56AGVQ

[tank0nf]

I will share a sample of it, but I have found this issue with every video I have tested

Thank you for the clarification. We’ve received the sample file and have already started working on resolving the issue.

Meanwhile, we would greatly appreciate your assistance in helping us cover all bases. Since you’ve mentioned encountering this issue with every video you’ve tested, could you kindly provide more details on the following:

1. How have you set up CCExtractor?
2. What specific errors are appearing in the other files?
3. Could you share the specifications of the other files you are referring to?

Your input will be incredibly helpful as we work to resolve the issue effectively.
Thank you,
Tank0nf.

[jaum20]

1. Standard Linux compilation through Autoconf scripts
2. Same error for all video files: No captions were found in input. Empty srt files are created
3. tested with my jellyfin library: all mkv files with embedded srt subs

Maybe the sample I provided wasn't the best because I created it using this command:
ffmpeg -i movie.mkv -ss 00:00:00 -t 15 -c copy sample_video.mkv
but not captions are shown in the first 15 secs

[jaum20]

Okay. That's weird. I created another sample, now in the middle of the movie and tested with ccextractor and it worked:

Opening file: sample_video.mkv
File seems to be a Matroska/WebM container
Analyzing data in Matroska mode


Document type: matroska
Timecode scale: 1000000
Muxing app: Lavf61.7.100
Writing app: Lavf61.7.100

Track entry:
    Track number: 1
    UID: 6468560451154994440
    Language: und
    Codec ID: V_MPEG4/ISO/AVC
    Type: video

Track entry:
    Track number: 2
    UID: 5573667526452854584
    Language: per
    Codec ID: A_AAC
    Type: audio

Track entry:
    Track number: 3
    UID: 7313999796934396663
    Language: eng
    Codec ID: S_TEXT/UTF8
    Type: subtitle
  0%  |  00:00
Found large gap(73) in PTS! Trying to recover ...

Found large gap(78) in PTS! Trying to recover ...

Found large gap(75) in PTS! Trying to recover ...

Found large gap(85) in PTS! Trying to recover ...

Found large gap(80) in PTS! Trying to recover ...

Found large gap(83) in PTS! Trying to recover ...
 99%  |  00:08
100%  |  00:08
Output file: sample_video_eng.srt

Found AVC track. 

Total frames time:	  00:00:06:773  (203 frames at 29.97fps)

Min PTS:				00:00:01:218
Max PTS:				00:00:10:084
Length:				 00:00:08:866
Done, processing time = 0 seconds
Issues? Open a ticket here
https://github.com/CCExtractor/ccextractor/issues

I can't understand how can it work with this 10 sec sample and not with the original video file. Maybe some metadata issue corrected by ffmpeg?

original file:

General
Unique ID                                : 171101638367894519736749109305634343285 (0x80B8FA153E3D9C78F39E852FB8264975)
Complete name                            :movie.mkv
Format                                   : Matroska
Format version                           : Version 4
File size                                : 8.56 GiB
Duration                                 : 1 h 42 min
Overall bit rate                         : 12.0 Mb/s
Frame rate                               : 23.976 FPS
Encoded date                             : 2024-12-29 04:57:58 UTC
Writing application                      : mkvmerge v65.0.0 ('Too Much') 64-bit
Writing library                          : libebml v1.4.2 + libmatroska v1.6.3 / Lavf58.76.100

Video
ID                                       : 1
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High@L5
Format settings                          : CABAC / 5 Ref Frames
Format settings, CABAC                   : Yes
Format settings, Reference frames        : 5 frames
Codec ID                                 : V_MPEG4/ISO/AVC
Duration                                 : 1 h 42 min
Bit rate                                 : 11.7 Mb/s
Width                                    : 1 920 pixels
Height                                   : 1 080 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Constant
Frame rate                               : 23.976 (24000/1001) FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 0.236
Stream size                              : 8.38 GiB (98%)
Writing library                          : x264 core 163 r3060 5db6aa6
Encoding settings                        : cabac=1 / ref=5 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=8 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=6 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=50 / rc=crf / mbtree=1 / crf=16.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / vbv_maxrate=12000 / vbv_bufsize=12000 / crf_max=0.0 / nal_hrd=none / filler=0 / ip_ratio=1.40 / aq=1:1.00
Default                                  : Yes
Forced                                   : No
Color range                              : Limited
Color primaries                          : BT.709
Transfer characteristics                 : BT.709
Matrix coefficients                      : BT.709

Audio
ID                                       : 2
Format                                   : AAC LC
Format/Info                              : Advanced Audio Codec Low Complexity
Codec ID                                 : A_AAC-2
Duration                                 : 1 h 42 min
Bit rate                                 : 256 kb/s
Channel(s)                               : 2 channels
Channel layout                           : L R
Sampling rate                            : 48.0 kHz
Frame rate                               : 46.875 FPS (1024 SPF)
Compression mode                         : Lossy
Stream size                              : 188 MiB (2%)
Language                                 : Persian
Default                                  : Yes
Forced                                   : No

Text
ID                                       : 3
Format                                   : UTF-8
Codec ID                                 : S_TEXT/UTF8
Codec ID/Info                            : UTF-8 Plain Text
Duration                                 : 1 h 40 min
Bit rate                                 : 46 b/s
Frame rate                               : 0.159 FPS
Count of elements                        : 958
Stream size                              : 34.3 KiB (0%)
Language                                 : English
Default                                  : Yes
Forced                                   : No

Menu
00:00:00.000                             : en:Chapter 01
00:08:39.018                             : en:Chapter 02
00:17:55.866                             : en:Chapter 03
00:25:59.182                             : en:Chapter 04
00:34:13.509                             : en:Chapter 05
00:40:28.134                             : en:Chapter 06
00:47:16.875                             : en:Chapter 07
00:54:35.814                             : en:Chapter 08
01:04:29.657                             : en:Chapter 09
01:12:22.046                             : en:Chapter 10
01:20:52.222                             : en:Chapter 11
01:30:53.823                             : en:Chapter 12

sample:

General
Unique ID                                : 231165434646090769881438910250179254446 (0xADE8D7E07DD83FD03A2E436F65FA58AE)
Complete name                            : sample_video.mkv
Format                                   : Matroska
Format version                           : Version 4
File size                                : 13.1 MiB
Duration                                 : 10 s 976 ms
Overall bit rate                         : 10.0 Mb/s
Frame rate                               : 14 642.509 FPS
Writing application                      : Lavf61.7.100
Writing library                          : Lavf61.7.100
ErrorDetectionType                       : Per level 1

Video
ID                                       : 1
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High@L5
Format settings                          : CABAC / 5 Ref Frames
Format settings, CABAC                   : Yes
Format settings, Reference frames        : 5 frames
Codec ID                                 : V_MPEG4/ISO/AVC
Duration                                 : 10 s 59 ms
Bit rate                                 : 11.7 Mb/s
Width                                    : 1 920 pixels
Height                                   : 1 080 pixels
Display aspect ratio                     : 16:9

Frame rate mode                          : Variable
Frame rate                               : 14 642.509 FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 0.000
Stream size                              : 8.38 GiB
Writing library                          : Lavc58.134.100 libx264
Default                                  : Yes
Forced                                   : No
Color range                              : Limited
Color primaries                          : BT.709
Transfer characteristics                 : BT.709
Matrix coefficients                      : BT.709

Audio
ID                                       : 2
Format                                   : AAC LC
Format/Info                              : Advanced Audio Codec Low Complexity
Codec ID                                 : A_AAC-2
Duration                                 : 10 s 16 ms
Bit rate                                 : 256 kb/s
Channel(s)                               : 2 channels
Channel layout                           : L R
Sampling rate                            : 48.0 kHz
Frame rate                               : 46.875 FPS (1024 SPF)
Compression mode                         : Lossy
Delay relative to video                  : -1 s 209 ms
Stream size                              : 188 MiB
Language                                 : Persian
Default                                  : Yes
Forced                                   : No

Text
ID                                       : 3
Format                                   : UTF-8
Codec ID                                 : S_TEXT/UTF8
Codec ID/Info                            : UTF-8 Plain Text
Duration                                 : 10 s 976 ms
Bit rate                                 : 46 b/s
Frame rate                               : 87.281 FPS
Count of elements                        : 958
Stream size                              : 34.3 KiB (0%)
Language                                 : English
Default                                  : Yes
Forced                                   : No

Menu
00:00:00.000                             : Chapter 01

new sample: https://limewire.com/d/8e065783-f3b2-4e92-8c72-0421de692667#JmIL9d4lB_4yfjvFgMp-aUa-WotKFxIg8gg3zgLfFN0