title: How to reduce bitrate with out change video quality in FFMPEG
body: <p>I'm using FFMPEG C library. I'm use modified <a href="https://ffmpeg.org/doxygen/trunk/muxing_8c-source.html" rel="nofollow noreferrer">muxing.c</a> example to encode video. Video quality is reduce frame by frame when I control bitrate (like 1080 x 720 - bitrate 680k ). But same image I using FFMPEG command line tool to encode same bitrate 680k image quality to not change.</p>
  <p>What is the reason for same image and bitrate encoded video quality reduce whan I encode using C API and reason why quality did not change command line tool.</p>
  <p>I use :</p>
  <p>Command line arg :</p>
  <ul>
  <li><code>ffmpeg -framerate 5 image%d.jpg  -c:v libx264 -b:v 64k -pix_fmt yuv420p out.mp4</code></li>
  </ul>
  <p>Muxing.c(modified) Codec setting :</p>
  <ul>
  <li><code>fps = 5;</code></li>
  <li><code>CODEC_ID = H264 (libx264);</code></li>
  <li><code>Pixel_fmt = yuv420;</code></li>
  <li><code>Image decoder = MJPEG;</code></li>
  <li><code>bitrate = 64000;</code></li>
  </ul>
  <p>The video size are same but quality is reduce frame by frame in muxing.c
  but same bitrate video quality is perfect.</p>
  <p>please provide how to I reduce bitrate with out change quality using FFMPEG C API.</p>