user12596: I am attempting to encode "ProRes 4444" movies with ffmpeg.  Some research led me to the "prores_ks" encoder, which is the only one of ffmpeg's prores encoders that supports "4444".
I used this command to test it out (input excluded):
-c:v prores_ks -f mov -profile:v 4444 test.mov

This produces a ProRes 4444 movie.  However, the colors appear darker than the original input.  After some research I came upon this option:
-vf colormatrix=bt601:bt709

Adding this filter seems to fix the problem.  However, the file size is for some reason considerably bigger.  Also, I do not like the idea that a filter has to be performed during this encoding, as I want the highest possible quality.  Does anyone know of a way to overcome this "color shift" without a video filter?

user12596: I believe the problem lies in how FFMPEG does the RGB->YUV conversion by default.  This option specifies the use of the bt709 color space for the conversion, instead of the default of bt601.  This fixes it for me - though please let me know if I'm doing something bad here!
-vf scale=out_color_matrix=bt709


12596: <p>I am attempting to encode "ProRes 4444" movies with ffmpeg.  Some research led me to the "prores_ks" encoder, which is the only one of ffmpeg's prores encoders that supports "4444".</p>

<p>I used this command to test it out (input excluded):</p>

<pre><code>-c:v prores_ks -f mov -profile:v 4444 test.mov
</code></pre>

<p>This produces a ProRes 4444 movie.  However, the colors appear darker than the original input.  After some research I came upon this option:</p>

<pre><code>-vf colormatrix=bt601:bt709
</code></pre>

<p>Adding this filter seems to fix the problem.  However, the file size is for some reason considerably bigger.  Also, I do not like the idea that a filter has to be performed during this encoding, as I want the highest possible quality.  Does anyone know of a way to overcome this "color shift" without a video filter?</p>
 12596: <p>I believe the problem lies in how FFMPEG does the RGB->YUV conversion by default.  This option specifies the use of the bt709 color space for the conversion, instead of the default of bt601.  This fixes it for me - though please let me know if I'm doing something bad here!</p>

<pre><code>-vf scale=out_color_matrix=bt709
</code></pre>
