Why are my transcoded videos coming out too large?

If your transcoded videos are ending up too large, the usual cause is that the encode settings are allowing too many bits per second for the content.

Common reasons:

1. Bitrate is set too high

   • Video size is mostly determined by bitrate and duration.
   • If you use a constant bitrate, or a CRF/quality setting that targets high quality, files can stay large or even grow larger than expected.

2. The source was already highly compressed

   • Re-encoding a video that’s already compressed often doesn’t reduce size much.
   • Sometimes it gets larger because the encoder uses a less efficient codec or higher quality settings.

3. Wrong codec or preset

   • Using a less efficient codec, or a very slow/high-quality preset, can produce large files.
   • For example, H.264 is usually smaller than older codecs, and H.265/AV1 can be smaller still at the cost of more CPU.

4. Resolution or frame rate wasn’t reduced

   • If you keep the same resolution and FPS, you need a lower bitrate to get a smaller file.
   • High-resolution or high-FPS video needs more data.

5. Audio settings are too generous

   • Audio can also bloat size if you keep a high bitrate, multiple audio tracks, or unneeded channels.
   • Example: stereo AAC at 128–192 kbps is usually enough for many uses.

6. Variable bitrate / quality mode chosen poorly

   • In tools like HandBrake, FFmpeg, etc., “quality” settings can be misleading.
   • A low numerical CRF means higher quality and larger files; a high RF/CRF means smaller files and lower quality.

7. Two-pass not used when targeting a size

   • If you want a specific final size, one-pass encoding may overshoot.
   • Two-pass encoding helps hit a target bitrate more accurately.

8. Filters or extra streams add overhead

   • Subtitles, multiple audio tracks, attachments, or chapters usually don’t add much, but can contribute.
   • Some containers also have slight overhead.

What to check

• What codec are you using?
• What bitrate or CRF/RF value?
• Did you change resolution/frame rate?
• Are you copying the audio, or re-encoding it?
• Is the source already compressed?

Quick rule of thumb

If you want smaller files:

• lower the video bitrate, or
• increase CRF/RF number slightly, or
• reduce resolution/FPS, or
• use a more efficient codec.

If you want, I can help you diagnose it precisely if you paste your encode command or HandBrake settings.