How to take perfect screenshots of UHD/HEVC vídeos?

[kdantas]

Hi, could someone give a tip to improve the quality of screenshots taken from UHD/HEVC files of seedbox running rtorrent/rutorrent installed on Ubuntu Server Armhf 16.04 "Xenial Xerus" (32bits) OS? Many screenshots are shown without any image definition. I don´t have problem with the screenshots of FHD videos. The screenshot plugin use the ffmpeg software. I don´t know if is necessary any adjust in the lines codes of plugins, or if exist a best way to take perfect screenshots of UHD videos through the terminal SSH?

[Hoser Rob]

Try Shutter and max out the quality rate.

[sneaker]

What container are the files in? (mkv, ts, ..??)
What is the ffmpeg command and complete log?
What version of ffmpeg are you using? From what I understand with that distribution it is often the version from back when the distribution was initially released plus a few cherry-picked security fixes. I.e. any other bug fixes of e.g. HEVC in mkv handling are not in there?

[kdantas]

What container are the files in? (mkv, ts, ..??)
What is the ffmpeg command and complete log?
What version of ffmpeg are you using? From what I understand with that distribution it is often the version from back when the distribution was initially released plus a few cherry-picked security fixes. I.e. any other bug fixes of e.g. HEVC in mkv handling are not in there?

Hi @sneaker, thanks for your reply.

1. What container are the files in? (mkv, ts, ..??)
I verified that the problem occur with .m2ts UHD files. I tested the screenshot plugin with .mkv UHD files and didn´t have problems.

2. What is the ffmpeg command and complete log?
I am running the screenshot plugin from rutorrent gui. So, don´t have any command or log.

3. What version of ffmpeg are you using?
$ ffmpeg -version
ffmpeg version 2.8.6-1ubuntu2 Copyright (c) 2000-2016 the FFmpeg developers
built with gcc 5.3.1 (Ubuntu/Linaro 5.3.1-11ubuntu1) 20160311
configuration: --prefix=/usr --extra-version=1ubuntu2 --build-suffix=-ffmpeg --toolchain=hardened --libdir=/usr/lib/arm-linux-gnueabihf --incdir=/usr/include/arm-linux-gnueabihf --cc=cc --cxx=g++ --enable-gpl --enable-shared --disable-stripping --disable-decoder=libopenjpeg --disable-decoder=libschroedinger --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librtmp --enable-libschroedinger --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzvbi --enable-openal --enable-opengl --enable-x11grab --enable-libdc1394 --enable-libiec61883 --enable-libzmq --enable-frei0r --enable-libx264 --enable-libopencv
libavutil 54. 31.100 / 54. 31.100
libavcodec 56. 60.100 / 56. 60.100
libavformat 56. 40.101 / 56. 40.101
libavdevice 56. 4.100 / 56. 4.100
libavfilter 5. 40.101 / 5. 40.101
libavresample 2. 1. 0 / 2. 1. 0
libswscale 3. 1.101 / 3. 1.101
libswresample 1. 2.101 / 1. 2.101
libpostproc 53. 3.100 / 53. 3.100

[kdantas]

Try Shutter and max out the quality rate.

I don´t know if the Shutter software can solve my problem, because I use the screenshot plugin from rutorrent gui.

[sneaker]

I verified that the problem occur with .m2ts UHD files. I tested the screenshot plugin with .mkv UHD files and didn´t have problems.

Ok, this is then a limitation of ffmpeg. In ts it doesn't have any index for safe (input) seeking. The references for the HEVC decoding are missing so only I frames decode correctly. I recommend using a different software for screenshots.

[kdantas]

I verified that the problem occur with .m2ts UHD files. I tested the screenshot plugin with .mkv UHD files and didn´t have problems.

Ok, this is then a limitation of ffmpeg. In ts it doesn't have any index for safe (input) seeking. The references for the HEVC decoding are missing so only I frames decode correctly. I recommend using a different software for screenshots.

So, do you have any suggestion of software/plugin to install in my seedbox to take perfect screenshots of .m2ts UHD files?

[sneaker]

If you were using a GUI I'd say just use a player like mpv or VLC but you are only using terminal?
It's a bit tricky, then. With ffmpeg you could use combined input and output seeking. The input point should be before a keyframe, the output point after it. If your source has a keyframe interval of 1 second then this should be safe (screenshot at 01:20:17):
ffmpeg -ss 01:20:15 -i "input.ts" -ss 00:00:02 -frames:v 1 "output.jpg"
(Increase the second seeking value if your source has a bigger keyframe interval.)

https://trac.ffmpeg.org/wiki/Seeking#Combinedseeking

[Hoser Rob]

Can you actually play UHD video? Because AFAIK you can't take a screenshot bigger than the screen res you have.

[kdantas]

If you were using a GUI I'd say just use a player like mpv or VLC but you are only using terminal?
It's a bit tricky, then. With ffmpeg you could use combined input and output seeking. The input point should be before a keyframe, the output point after it. If your source has a keyframe interval of 1 second then this should be safe (screenshot at 01:20:17):
ffmpeg -ss 01:20:15 -i "input.ts" -ss 00:00:02 -frames:v 1 "output.jpg"
(Increase the second seeking value if your source has a bigger keyframe interval.)

https://trac.ffmpeg.org/wiki/Seeking#Combinedseeking

Hi @sneaker, If I am running ruTorrent Gui, I really don´t know how to use a player to take screenshots. I think is not possible. But I will test ffmpeg via terminal.

[kdantas]

Can you actually play UHD video? Because AFAIK you can't take a screenshot bigger than the screen res you have.

Hi @Hoser, I just want to take screenshots of videos files that are in my seedbox. In this case, .m2ts files.

[kdantas]

Can you actually play UHD video? Because AFAIK you can't take a screenshot bigger than the screen res you have.

Duplicated!!!