[FFmpeg-user] gain the highest quality with H264 at a certain bit rate

negin tebyani negin.tebyani at gmail.com
Mon Mar 27 19:51:36 EEST 2017


I used this command but the quality is still the same. does deblock has
something to do with this? the second video that I want to reach has
smoother frames, mine seems to have a lot of noise.

On Mon, Mar 27, 2017 at 8:22 PM, chronek <chronek at interia.eu> wrote:

> So you set own x264opts then you use preset slow what rewrite x264opts..
>
> If you reencode h264 with downsacale try with minimal settings like:
>
>
> ffmpeg -y -i in.mp4 -vf pp=va/ha,scale=1280:720:flags=
> spline+full_chroma_inp+full_chroma_int+accurate_rnd+bitexact,setsar=1 -an
> -c:v libx264 -preset veryslow -b:v 2048k -pass 1 /dev/null
>
> ffmpeg -y -i in.mp4 -vf pp=va/ha,scale=1280:720:flags=
> spline+full_chroma_inp+full_chroma_int+accurate_rnd+bitexact,setsar=1
> -c:a aac -b:a 128k -c:v libx264 -preset veryslow -b:v 2048k -pass 2 out.mp4
>
>
> Btw. i found that sometimes better is using crf than constant bitrate (use
> something like -crf 22 instead with single pass) you could
> unsharp=7:7:0.5:7:7:0.5 before scale and if you compile ffmpeg try with
> -fno-fast-math
>
>
> W dniu 2017-03-27 o 14:21, negin tebyani pisze:
>
>> I have encoded my videos using ffmpeg and H264, and this is my ffmpeg
>> command (2 pass encoding):
>>
>> ffmpeg -y -i Edited\ Clips/arsenalVScristalPalas.mp4 -movflags faststart
>> -c:v libx264 -x264opts
>> 'keyint=300:min-keyint=25:8x8dct:sliced-threads=0:subq=6' -deblock 0:0
>> -flags +loop -preset slow -tune zerolatency -b:v 2048k -maxrate 2048k
>> -bufsize 3000k -vf "scale=-1280:720" -pass 1 -acodec libmp3lame -b:a 128k
>> -coder 1 -me_range 16 -sc_threshold 42 -bf 10 -qmin 0 -qmax 51 -trellis 2
>>
>>
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