[FFmpeg-user] Quality Reduced when Burning Subtitles

Michael Koch astroelectronic at t-online.de
Mon Sep 13 11:55:01 EEST 2021

Am 13.09.2021 um 10:42 schrieb Veronica & Stephen McGuckin:
> Thank you. Please can you explain a little bit more about what option I should set.
> Regards
> -----Original Message-----
> From: ffmpeg-user <ffmpeg-user-bounces at ffmpeg.org> On Behalf Of Paul B Mahol
> Sent: 11 September 2021 16:54
> To: FFmpeg user questions <ffmpeg-user at ffmpeg.org>
> Subject: Re: [FFmpeg-user] Quality Reduced when Burning Subtitles
> Next time set option for overlay filter.
> On Sat, Sep 11, 2021 at 5:47 PM Veronica & Stephen McGuckin < VSMcGuckin at outlook.com> wrote:
>> Hello,
>> I am trying to overlay pgs subtitles onto a 4K video. I have extracted
>> 10 minute to make sure I have the correct ffmpeg coding. The input
>> file is 5.6 gigabytes with a bit rate of 78.6 Mb/s. I am using the
>> following ffmpeg commands.
>> ffmpeg -i c:\video\input.mkv -filter_complex “[0:v][0:s]overlay[v]”
>> -c:v
>> libx265 -pix_fmt yuv420p10le -profile:v high  -x265-params “-crf=10
>> -film
>> -hdr10+=1 -preset slow” -map “[v]” -map 0:a:0 -c:a copy
>> -hdr10+c:\video\output.mkv

overlay=format=yuv420p10  (or whatever the pixel format of the input 
streams is)
If you don't specify the format, the default would be yuv420 (which is 


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