user11551: ffmpeg -pix_fmts lists many pixel formats. In my ffmpeg, there are 66 different pixel formats that start with yuv. A few of them are familiar to me (e.g., yuv422p), but most of them are not (e.g., yuva422p16be).
Where are these pixel formats defined?

user11645: If your question was

Where are these pixel formats defined?

Go to http://ffmpeg.org/download.html and download the source of ffmpeg. Then unpack it
tar -xavf FILENAME.tar.*

and descend to the folder in the source code that is called libavutil
cd ffmpeg-*/libavutil/

and open the file pixfmt.h where you will find a description of all pixel formats. A few sample lines
AV_PIX_FMT_YUV420P,   ///< planar YUV 4:2:0, 12bpp, (1 Cr & Cb sample per 2x2 Y samples)          
AV_PIX_FMT_YUYV422,   ///< packed YUV 4:2:2, 16bpp, Y0 Cb Y1 Cr
AV_PIX_FMT_RGB24,     ///< packed RGB 8:8:8, 24bpp, RGBRGB...
AV_PIX_FMT_BGR24,     ///< packed RGB 8:8:8, 24bpp, BGRBGR...
AV_PIX_FMT_YUV422P,   ///< planar YUV 4:2:2, 16bpp, (1 Cr & Cb sample per 2x1 Y samples)

Additionally you can read https://en.wikipedia.org/wiki/YUV and it’s cited sources and external links.

11551: <p><code>ffmpeg -pix_fmts</code> lists many pixel formats. In my ffmpeg, there are 66 different pixel formats that start with <em>yuv</em>. A few of them are familiar to me (e.g., yuv422p), but most of them are not (e.g., yuva422p16be).</p>

<p>Where are these pixel formats defined?</p>
 11645: <p>If your question was</p>

<blockquote>
  <p>Where are these pixel formats defined?</p>
</blockquote>

<p>Go to <a href="http://ffmpeg.org/download.html" rel="noreferrer">http://ffmpeg.org/download.html</a> and download the source of ffmpeg. Then unpack it</p>

<pre><code>tar -xavf FILENAME.tar.*
</code></pre>

<p>and descend to the folder in the source code that is called <code>libavutil</code></p>

<pre><code>cd ffmpeg-*/libavutil/
</code></pre>

<p>and open the file <code>pixfmt.h</code> where you will find a description of all pixel formats. <strong>A few sample lines</strong></p>

<pre><code>AV_PIX_FMT_YUV420P,   ///&lt; planar YUV 4:2:0, 12bpp, (1 Cr &amp; Cb sample per 2x2 Y samples)          
AV_PIX_FMT_YUYV422,   ///&lt; packed YUV 4:2:2, 16bpp, Y0 Cb Y1 Cr
AV_PIX_FMT_RGB24,     ///&lt; packed RGB 8:8:8, 24bpp, RGBRGB...
AV_PIX_FMT_BGR24,     ///&lt; packed RGB 8:8:8, 24bpp, BGRBGR...
AV_PIX_FMT_YUV422P,   ///&lt; planar YUV 4:2:2, 16bpp, (1 Cr &amp; Cb sample per 2x1 Y samples)
</code></pre>

<p>Additionally you can read <a href="https://en.wikipedia.org/wiki/YUV" rel="noreferrer">https://en.wikipedia.org/wiki/YUV</a> and it’s cited sources and external links.</p>
