Subtitles provided using stdin pipes or http/https does not work correctly

[gregkoganvmm]

• I looked for a similar issue and couldn't find any.
• I tried with the latest version of GPAC. Installers available at https://gpac.io/downloads/gpac-nightly-builds/
• I give enough information for contributors to reproduce my issue (meaningful title, github labels, platform and compiler, command-line ...)

Platform: linux/amd64 (Ubuntu 22.04) or macOS Sonoma 14.4.1

Hello,

Subtitles provided using stdin pipes or http/https does not work correctly - the output is either empty or corrupted.

gpac -i "https://download.blender.org/demo/movies/ToS/subtitles/TOS-en.srt" -o stdout:ext=vtt

[TXTIn] Corrupted SRT frame 12 after frame 1
WEBVTT

00:23.000 --> 00:24.500
etty freaky.

cat TOS-en.srt|gpac -no-block=all -i stdin -o stdout:ext=vtt produces nothing

There is a workaround to make it work (hope this helps someone) - adding the -no-block=all parameter helps in both cases, but this is hardly obvious. See the full command below:
cat TOS-en.srt|gpac -no-block=all -i stdin -o stdout:ext=vtt

gpac -no-block=all -i "https://download.blender.org/demo/movies/ToS/subtitles/TOS-en.srt" -o stdout:ext=vtt

[rbouqueau]

Thanks for reporting and documenting the issue. We're a bit slower than usual to process issues, thanks for your patience.