Tech Tip - Converting captioned MXF files into captioned transport streams

PixelTools products can extract closed caption, video and audio tracks from an MXF file, embed the captions into the video and multiplex with the audio to create a MPEG stream for broadcast. The process is accomplished without transcoding and thus maintains original content quality and processes very fast.

The MXF file format is popular for editing video content but not well suited for broadcast.   Many broadcasters require content be delivered in an MPEG transport stream with CEA-708 and CEA-608 captions embedded in the elementary video user_data.

PixelTools Expert-Caption and MPEGRepairHD can split MXF files into their elementary components, insert the MXF’s closed caption track into the elementary video and then multiplex the captioned video with the audio track(s) into an ATSC/VOD compliant MPEG-2 transport stream.

Operational Details

MPEGRepairHD and Expert-Caption can accomplish the MXF caption conversion using a simple call in the batch processing mode or running several conversion passes in the GUI mode.


Batch Processing of MXF Files

MPEGRepairHD and Expert-Caption can be easily called from a batch command to cause your MXF file to be converted to MPG file.

The Syntax

ExpCap TheBartlets.Mxf -MX  will cause TheBartlets.Mxf MXF file to be split, re-captioned, and multiplexed into a MPEG transport stream called TheBartletsCC.Mpg

GUI Processing of MXF Files

Your MXF files can be processed to MPEG under GUI controls without transcoding. This is a three step process as follows:

1. First split the .MXF file into its video, audio, and captioning components using the Decode | Extract Streams dialog and running the decode on your MXF file:

Speed up the process by checking the Decode  Configure | Disable Decode option.

2. Next embedd the extracted captions (saved in the PixelTools .edl format in the previous step) into the extracted elementary video.

Select the ExtractElem.vbs video in the File to Decode or Analyze edit box on the Decode section of the GUI and set up the Decode | Fix Stream dialog to Add Closed Captions from the .Edl file:


Again, you can speed up the process by checking the Decode  Configure | Disable Decode option.

3. Finally, multiplex your captioned video file with the extracted audio file into a MPEG transport stream by setting up the Configure Audio/Mux dialog as illustrated below.

Browse or enter your elementary captioned video, elementary audio, and resultant multiplexed .mpg file name in the appropriate edit box.  Depress the Control |  Run button on this dialog to multiplex your video and audio.


The Transport Stream with captioned video and MPEG encoded audio will be saved in the file designated.

PixelTools MPEGRepairHD can be used to convert MXF files to MPG files using the tool’s mostly identical control dialogs.

Click here to see how PixelTools Expert-Caption and MPEGRepairHD can easily extract closed captions stored in an MXF caption track and save them in a PixelTools caption file format that can be used for re-insertion into the video track in support of broadcast video.

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MPEGRepairHD, Expert-HD, Expert-Caption and Expert-Broadcast are trademarks of PixelTools Corporation. All other brand names are trademarks or registered trademarks of their respected holders.

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