[FFmpeg-devel] [PATCH v5 00/25] Subtitle Filtering 2022

[Soft Works]

> -----Original Message-----
> From: ffmpegagent <ffmpegagent at gmail.com>
> Sent: Saturday, June 25, 2022 11:58 AM
> To: ffmpeg-devel at ffmpeg.org
> Cc: Michael Niedermayer <michael at niedermayer.cc>; Andreas Rheinhardt
> <andreas.rheinhardt at outlook.com>; Soft Works <softworkz at hotmail.com>;
> Andriy Gelman <andriy.gelman at gmail.com>; softworkz
> <softworkz at hotmail.com>
> Subject: [PATCH v5 00/25] Subtitle Filtering 2022
> 
> 
> Subtitle Filtering 2022
> =======================
> 
> This is a substantial update to the earlier subtitle filtering patch
> series.
> A primary goal has been to address others' concerns as much as
> possible on
> one side and to provide more clarity and control over the way things
> are
> working. Clarity is is specifically important to allow for a better
> understanding of the need for a subtitle start pts value that can be
> different from the frame's pts value. This is done by refactoring the
> subtitle timing fields in AVFrame, adding a frame field to indicate
> repeated
> subtitle frames, and finally the full removal of the heartbeat
> functionality, replaced by a new 'subfeed' filter that provides
> different
> modes for arbitrating subtitle frames in a filter graph. Finally,
> each
> subtitle filter's documentation has been amended by a section
> describing the
> filter's timeline behavior (in v3 update).
> 
> 
> Subtitle Filtering Demos
> ========================
> 
> I published a demonstration of subtitle filtering capabilities with
> OCR,
> text and bitmap subtitle manipulation involved: Demo 1: Text-
> Manipulation
> with Bitmap Subtitles
> [https://github.com/softworkz/SubtitleFilteringDemos/tree/master/Demo
> 1]


As there were no objections in any regard, I hope that we could make 
some progress regarding subtitle filtering soon.

The only recent statement that has been made was something like

"this may work in a limited number of cases but probably won't be 
capable to work for the whole range of real-life situations"

I understand how easily such statements can induce doubt into the 
audience, even on those who tend and try to be neutral in their 
assessments. I also think that replying once another time with 
something like "no, this isn't true" won't be much impressive.


Instead, I'm sharing a video with you, documenting my internal
test runs for text subtitle overlay (with and without subtitle 
filtering, with and without hw overlay, with a range of hw accelerations 
for encoding and decoding, scaling or no scaling and two different 
kinds of source files).

The diagrams at the right are a rather consumer focused, but still 
accurate. Just hwupload/download/hwmap are omitted and implied
by the data changing the "swim lanes".

https://github.com/softworkz/SubtitleFilteringDemos/tree/master/TestRun1

Commands and logs on request.

Best wishes,
softworkz