Tech Tips - Transcoding


MPEGRepairHD can easily convert encoded content from one MPEG file format to another MPEG or H.264 file format.  This is accomplished in a single pass that decodes each frame to memory and immediately re-encodes the frame.  All pre-processing down-sampling, up-sampling and filtering operations can be utilized in the transcoding process. 

Transcoding is excellent for:

  1. Converting MPEG-1 to MPEG-2
  2. Changing bit-rate
  3. Changing frame size
  4. Converting MPEG to H.264 (AVC)
  5. Converting Long GOP to I frame only or visa versa
  6. Filtering noisy videos
  7. Adding logos or sub-tiles
  8. Converting graphics levels to video levels

It should be noted that some stream processes that involve encoding flag updates can be accomplished with the Decode Fix options that do not involve decoding and re-encoding.

Transcoding using MPEGRepairHD GUI

The transcoding process is accomplished by selecting the MPEG encoded source (that you wish to transcode) in the “Encode Input” edit box.  MPEGRepairHD recognizes all MPEG sources (including Transport, VOB, Program, System, and Elementary streams) and automatically decodes each frame before it is re-encoded using your selected encoding parameters.  PreProcessing re-sizing filters can be utilized provided that the source MPEG conforms to the filter’s input size and the re-encoded MPEG conforms to the filter’s output size.

You also can transcode from any MPEG source to an H.264 video by again selecting the MPEG source in the “Encode Input” edit box and checking the H.264 encode option in the H.264 Property Page.  Note that you must set the H.264 frame size in the H.264 property page to that of the source MPEG or pre-processed MPEG.


Transcoding using Expert WorkShop SDKencoding example

Transcoding using the Expert WorkShop SDK can be accomplished by sequentially calling DecodeNextFrame and the EncodeNextFrame for the entire video.  Use the decode to buffer and encode from buffer modes.  Note that the very first call to DecodeNextFrame will not always return a decoded frame as it is sometimes saved as a reference frame in the decoder’s memory. Click on image to see full screen.




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