<p>Judge based on the quality rather than the bitrate value. Use CRF mode encoding and if the quality isn't what you can accept, decrease the CRF value.</p>

<pre><code>ffmpeg -i "%%a" -s 3840x2610 -c:v libx264 -crf 18 -acodec copy D:\%%~na.mp4
</code></pre>

CC BY-SA 3.0
2015-11-01T16:02:42.197Z
Is it possible to say which -crf gets me the same quality as the original?
screenfun2312
CC BY-SA 3.0
2015-11-01T16:07:06.273Z
CRF 18 is advertised as 'visually lossless', but isn't technically lossless. See http://slhck.info/articles/crf
Gyan
CC BY-SA 3.0
2015-11-01T21:02:55.090Z
Alternatively you could use `-vf scale=3840:-1`.
llogan
CC BY-SA 3.0
2015-11-01T15:45:35.690Z
2015-11-01T15:45:35.690Z
Gyan
<p>I have recently come into possession of a couple of 4k movies with a resolution of 4096x2304. Unfortunately my Samsung 4k TV wont play anything over 3840x2160.</p>

<p>I have managed to re-encode the videos to 3840x2160, unfortunately the bitrate fell to 1/10th of what it was before.</p>

<p>I used:</p>

<pre><code>for %%a in ("*.mkv") do ffmpeg -i "%%a" -s 3840x2610 -q:v 0 -c:v libx264 -acodec copy D:\%%~na.mp4
</code></pre>

<p>Original file size was 27.8GB, the re-encoded one was under 8GB.</p>

<p>Is there any way I can re-encode them so I can keep the original bitrate/quality?</p>

<blockquote>
  <p>Rant: Even my 4 year old computer can play the movie, but that fcking
  new Samsung TV of course can't /rant-end</p>
</blockquote>

<ffmpeg><encoding><conversion><4k>
Convert resolution 4096x2304 to 3840x2160 keeping the quality the same
screenfun2312
# Convert resolution 4096x2304 to 3840x2160 keeping the quality the same

(Asked by: username_0 on 2015-11-01)

I have recently come into possession of a couple of 4k movies with a resolution of 4096x2304. Unfortunately my Samsung 4k TV wont play anything over 3840x2160.
I have managed to re-encode the videos to 3840x2160, unfortunately the bitrate fell to 1/10th of what it was before.
I used:
for %%a in ("*.mkv") do ffmpeg -i "%%a" -s 3840x2610 -q:v 0 -c:v libx264 -acodec copy D:\%%~na.mp4

Original file size was 27.8GB, the re-encoded one was under 8GB.
Is there any way I can re-encode them so I can keep the original bitrate/quality?

Rant: Even my 4 year old computer can play the movie, but that fcking
  new Samsung TV of course can't /rant-end

**Tags:** ffmpeg, encoding, conversion, 4k


---

## 1 answers

### Answer by username_1 on 2015-11-01. Score: 3 | Accepted answer

Judge based on the quality rather than the bitrate value. Use CRF mode encoding and if the quality isn't what you can accept, decrease the CRF value.
ffmpeg -i "%%a" -s 3840x2610 -c:v libx264 -crf 18 -acodec copy D:\%%~na.mp4

> **Comments:**
> **username_0**: Is it possible to say which -crf gets me the same quality as the original?  
> **username_1**: CRF 18 is advertised as 'visually lossless', but isn't technically lossless. See http://slhck.info/articles/crf  
> **username_2**: Alternatively you could use `-vf scale=3840:-1`.  

---

