[FIX] Handle row_count decrease

[moveman]

In raising this pull request, I confirm the following (please check boxes):

• I have read and understood the contributors guide.
• I have checked that another pull request for this purpose does not exist.
• I have considered, and confirmed that this submission will be valuable to others.
• I accept that this submission may not be used, and the pull request closed at the will of the maintainer.
• I give this submission freely, and claim no ownership to its content.
• I have mentioned this change in the changelog.

My familiarity with the project is as follows (check one):

• I have never used CCExtractor.
• I have used CCExtractor just a couple of times.
• I absolutely love CCExtractor, but have not contributed previously.
• I am an active contributor to CCExtractor.

---

We found ccextractor cannot handle row_count decreasing well. When row count decreases, the upper row should be displaced while the bottom row should be kept.
Before the fix, the srt is like this:

104
00:04:05,795 --> 00:04:06,295
{\an4}A roll-up caption's depth

105
00:04:07,296 --> 00:04:07,330
{\an4}A roll-up caption's depth

106
00:04:08,264 --> 00:04:08,297
{\an4}A roll-up caption's depth

107%  |  04:11
00:04:08,298 --> 00:04:12,034
{\an2}A roll-up caption's depth
displayed, like this.

108%  |  04:14
00:04:12,068 --> 00:04:14,770
{\an5}(CC1) Demonstration of
paint-on style captions:

After the fix, the srt is like this:

104
00:04:05,795 --> 00:04:06,295
{\an4}A roll-up caption's depth

105
00:04:07,296 --> 00:04:07,330
{\an4}A roll-up caption's depth
can be decreased after

106
00:04:08,264 --> 00:04:08,297
{\an2}can be decreased after
the caption has been

107%  |  04:11
00:04:08,298 --> 00:04:12,034
{\an2}the caption has been
displayed, like this.

108%  |  04:14
00:04:12,068 --> 00:04:14,770
{\an5}(CC1) Demonstration of
paint-on style captions:

The cea708 log of the original ccExtractor is included here:
708.log

The cea708 log of the fixed ccExtractor is included here:
new_708.log

Expected captions:

[cfsmp3]

LGTM, but be aware that since we are migrating to Rust it's possible this change gets lost if not ported.

[steel-bucket]

Hi, can you please rebase so we could check the regression tests.
Thanks

[prateekmedia]

Would it be possible for you to change it to single if instead like:

if (window->is_defined && row_count <...) {
    for (...
}

[prateekmedia]

LGTM! If you can resolve comment then fine, otherwise we can merge as is.

[ccextractor-bot]

CCExtractor CI platform finished running the test files on linux. Below is a summary of the test results, when compared to test for commit 60ae6fb...:

Report Name	Tests Passed
Broken	13/13
CEA-708	14/14
DVB	7/7
DVD	3/3
DVR-MS	2/2
General	27/27
Hardsubx	0/1
Hauppage	3/3
MP4	3/3
NoCC	10/10
Options	86/86
Teletext	21/21
WTV	13/13
XDS	34/34

Your PR breaks these cases:

• ccextractor --hardsubx 1a0302f7fd...

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.

[ccextractor-bot]

CCExtractor CI platform finished running the test files on windows. Below is a summary of the test results, when compared to test for commit da03c1e...:

Report Name	Tests Passed
Broken	13/13
CEA-708	14/14
DVB	4/7
DVD	3/3
DVR-MS	2/2
General	27/27
Hardsubx	0/1
Hauppage	3/3
MP4	3/3
NoCC	10/10
Options	86/86
Teletext	7/21
WTV	13/13
XDS	34/34

Your PR breaks these cases:

• ccextractor --autoprogram --out=srt --latin1 f1422b8bfe...
• ccextractor --datapid 5603 --autoprogram --out=srt --latin1 --teletext 85c7fc1ad7...
• ccextractor --autoprogram --out=srt --latin1 --quant 0 85271be4d2...
• ccextractor --autoprogram --out=ttxt --latin1 c0d2fba8c0...
• ccextractor --autoprogram --out=ttxt --latin1 006fdc391a...
• ccextractor --autoprogram --out=ttxt --latin1 e92a1d4d2a...
• ccextractor --autoprogram --out=ttxt --latin1 7e4ebf7fd7...
• ccextractor --autoprogram --out=ttxt --latin1 9256a60e4b...
• ccextractor --autoprogram --out=ttxt --latin1 27d7a43dd6...
• ccextractor --autoprogram --out=ttxt --latin1 297a44921a...
• ccextractor --autoprogram --out=ttxt --latin1 efbe129086...
• ccextractor --autoprogram --out=ttxt --latin1 eae0077731...
• ccextractor --autoprogram --out=ttxt --latin1 e2e2b501e0...
• ccextractor --autoprogram --out=ttxt --latin1 c6407fb294...
• ccextractor --autoprogram --out=ttxt --latin1 --datets dcada745de...
• ccextractor --autoprogram --out=srt --latin1 --tpage 398 5d5838bde9...
• ccextractor --autoprogram --out=srt --latin1 --teletext --tpage 398 3b276ad8bf...

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

• ccextractor --hardsubx 1a0302f7fd..., Last passed:

  Test 6291

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.