Conversion of TS/H264 to MPG/H265 increasing file size?

General Support / Questions
2

It’s not uncommon to see a file size increase when transcoding between already compressed formats, even when moving from H.264 to the more efficient H.265 (HEVC). Based on similar discussions in the forum, here are a few reasons why this might be happening with your Emby (TS) recordings compared to your Channels DVR (MP4) recordings:

1. The “Quality” Setting and Multipliers

MCEBuddy profiles often use a Quality Multiplier or a constant quality factor (CRF).

  • If your profile is set to a high quality level, MCEBuddy will try to preserve as much detail as possible.
  • TS files (Transport Streams) from Emby are often “messier” than MP4s—they can contain transmission errors, interlacing, or extra metadata. When H.265 tries to “perfectly” encode that noise or interlacing at a high quality setting, it can actually use more bits than the original H.264 version did.
  • Check your log: Look for the -q or crf value being used by Handbrake or FFmpeg in the log you attached. If it’s very low (e.g., below 20 for H.265), it may be over-encoding.

2. Hardware vs. Software Encoding

Are you using a GPU (NVENC, QuickSync) for these conversions?

  • Hardware encoders are much faster but generally less efficient at compression than software encoding (x265).
  • If your Channels DVR files were highly compressed to begin with, a hardware H.265 encode might require a higher bitrate to maintain the same perceived quality, leading to a larger file.

3. Audio and Container Overhead

  • TS vs MPG: You mentioned converting to an MPG container. The MPEG-PS (Program Stream) container has different overhead than MP4 or MKV.
  • Audio: If the original TS file has AC3 audio and your profile is converting it to a higher bitrate or a different format (like AAC or PCM), the audio portion of the file could be growing.

4. Interlacing

Many Emby/Broadcast TS recordings are 1080i (interlaced).

  • If MCEBuddy is de-interlacing the video during the transcode, it is creating new frames.
  • H.265 handles progressive video much better than interlaced. If the source is interlaced and not being handled correctly by the profile, the encoder might struggle to compress it efficiently.

Suggested Next Steps:

  1. Lower the Quality Slider: Try moving the quality slider in your Conversion Task down by 5-10% to see if the file size drops without a noticeable loss in visual quality.
  2. Try MKV/MP4: Unless you specifically need .mpg for a legacy player, try using an MKV HEVC or MP4 HEVC profile. They are generally more modern and efficient.
  3. Check for “High Quality”: If you are using a “High Quality” profile, it is designed to prioritize video fidelity over file size. Switch to a “Normal” or “Fast” profile to see the difference.

You can find more advanced technical details on how to tweak these settings in the MCEBuddy Advanced Settings Guide.