[FFmpeg-user] Fwd: Remove black border on both up/down and left/bottom

[Richard Bartczak]

-------- Weitergeleitete Nachricht --------
Betreff: 	Re: [FFmpeg-user] Remove black border on both up/down and 
left/bottom
Datum: 	Fri, 23 May 2025 03:04:26 +0200
Von: 	Richard Bartczak <richard.bartczak at gmx.de>
An: 	Mark Filipak <markfilipak.imdb at gmail.com>



Am 23.05.25 um 02:53 schrieb Mark Filipak:
> On 22/05/2025 20.18, Richard Bartczak via ffmpeg-user wrote:
>> ffmpeg -i "1492-Die Eroberung  des Paradieses.ts" -crf 0 -vf 
>> scale=720x576,setsar=64/45,setdar=16/9 -c:a copy out.ts               
>> => bad quality, but speedx >= 8
>
> -vf scale=720x576,setsar=64/45,setdar=16/9
> You are causing the video steam to be decoded. You are then scaling 
> the pictures to 720x576 -- Why? You are then forcing SAR and DAR 
> before sending the pictures to the encoder. Since you don't specify an 
> encoder, the encoder is probably defaulting to MPEG2.
>
> -crf 0
> I've never used this bitstream function. Constant frame rate? Yes, it 
> probably is CFR, but why do you think you need to force it? Leave that 
> out.
>
> ** Oh, sorry. '-crf' is not constant frame rate.
> Documentation says, "Set the quality/size tradeoff for 
> constant-quality (no bitrate target) and constrained-quality (with 
> maximum bitrate target) modes. Valid range is 0 to 63, higher numbers 
> indicating lower quality and smaller output size. Only used if set; by 
> default only the bitrate target is used."
> That's too vague for me to figure out what it does.
>
> Stream #0:0[0x100]: Video: mpeg2video (Main) ([2][0][0][0] / 0x0002), 
> yuv420p(tv, bt470bg, top first), *720x576 [SAR 16:15 DAR 4:3]*, 25 
> fps, 25 tbr, 90k tbn
>
> Your video is 768x576 -- seems like standard PAL to me. That should 
> play fine without doing anything. If you are getting black bars all 
> around on play, I'd say your player is not scaling it to 1440x1080. It 
> it was scaling it properly, it should also add black bars on the 
> sides, only, to bring it to 1920x1080 display.
> _______________________________________________
> ffmpeg-user mailing list
> ffmpeg-user at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-user
>
> To unsubscribe, visit link above, or email
> ffmpeg-user-request at ffmpeg.org with subject "unsubscribe".

A description of crf you will find here : 
https://trac.ffmpeg.org/wiki/Encode/H.265

But it does not work in the context of -vf only (as example here : 
https://stackoverflow.com/questions/36966197/how-to-change-mp4-aspect-ratio-to-169-using-ffmpeg 
,

second answer.).

Best regards

Richard