[PROPOSAL] Display both EIA-608 fields in --out report by default

[bbgdzxng1]

Summary

By default, --out report will only report the presence of captions in the EIA-608 field 1. Captions in field 2 (CC3/4) are not detected by default. Currently, report will always explicitly state that there are no captions in CC3/4 unless the user passes --output-field 'both'.

The --out report is misleading to an end-user because it explicitly states there are no captions in CC3, whereas this is only the result of the defaults.

Proposal:

Either:

• a. report mode should not explicitly list CC channels which do not belong to the field being probed, or state unknown
• b. report mode should probe both EIA-608 fields by default --output-field 'both'. This is the more elegant solution suggested by @Varadraj75 at the end of this ticket.

Impact / Priority

• Low, because a known workaround exists & the functionality is all there today if the user passes the appropriate options. From an end user perspective, it is a minor usability inconvenience.

Sample File & Test Case

Download sample (copying to TS, just because of an unrelated issue of MPEG2 in MKV, which is already resolved in master)

Run ccextractor on TS input...

$ ffmpeg -i "https://weather.horse/samples/cc3.mkv" -c 'copy' "./cc3.ts" -y

$ ccextractor --out report "./cc3.ts" 
File: ./cc3.ts
Stream Mode: Transport Stream
Program Count: 1
Program Numbers: 1 
PID: 256, Program: 1, MPEG-2 video
PID: 257, Program: 1, AC3 audio
//////// Program #1: ////////
DVB Subtitles: No
Teletext: No
ATSC Closed Caption: Yes
EIA-608: Yes
XDS: No
CC1: No
CC2: No
CC3: No <<<<<<<<<<<<<<<<<<<<<< CC3 is not detected
CC4: No
CEA-708: No
Width: 720
Height: 480
Aspect Ratio: 02 - 4:3
Frame Rate: 04 - 29.97

MPEG-4 Timed Text: No

Workaround

Specify both fields during execution...

$ ccextractor --output-field 'both' --out 'report' -o - "./cc3.ts"
File: ./cc3.ts
Stream Mode: Transport Stream
Program Count: 1
Program Numbers: 1 
PID: 256, Program: 1, MPEG-2 video
PID: 257, Program: 1, AC3 audio
//////// Program #1: ////////
DVB Subtitles: No
Teletext: No
ATSC Closed Caption: Yes
EIA-608: Yes
XDS: No
CC1: No
CC2: No
CC3: Yes <<<<<<<<<<<<<<<<<<<<<<< CC3 is now detected if --output-field 'both' is used
CC4: No
CEA-708: No
Width: 720
Height: 480
Aspect Ratio: 02 - 4:3
Frame Rate: 04 - 29.97

MPEG-4 Timed Text: No

Also, errors with --stdout

Workaround is to use -o - rather than --stdout

$ ccextractor --output-field 'both' --out 'report' --stdout "./cc3.ts"
Error: You can't extract both fields to stdout at the same time in broadcast mode.

Discussion from other ticket

#2149 (comment)

@Varadraj75 wrote...

the report mode behavior is genuinely misleading.
CC3: No when the captions are actually there is worse than not showing CC3
at all, since it could make users conclude the file has no CC3 content.

I agree this deserves a separate ticket. The cleanest fix is probably to have
--out report internally use --output-field both for its analysis pass,
with the broadcast mode conflict handled gracefully (just suppress the error
when in report-only mode since there's no actual --stdout conflict).

@Varadraj75 I hope you are not offended in me resurfacing your previous reply and creating a separate, independent issue.

[Varadraj75]

I'd like to work on this — I'll submit a PR with option (b):
make report mode internally use --output-field both, with the
broadcast mode conflict suppressed gracefully in report-only mode.