- Stream Header Replacement
MPEGRepairHD can be used to modify stream headers
including time code, aspect ratio, pan and scan, etc. and can insert Closed
Captioning and CGMS flags all
without decoding and re-encoding the original MPEG stream.
A demonstration of the steam header replacement process can be obtained
at headerupdate.zip. Download
this file, unzip the directory structure and perform the sample header
update as detailed in the ReadMe.txt file. The demo includes
a sample MPEG encoded file. The ReadMe instructs you to
1. Analyze the sample MPEG and note its aspect ratio
2. Run the update aspect ratio process
3. Analyze the updated MPEG stream and note its updated aspect ratio.
Header Update using the MPEGRepairHD GUI
The MPEGRepair decode section includes the
ability to update stream headers without re-encoding. The Decode
| Configure | Fix Stream dialog controls the stream update process.
on image to see larger size
Selecting any of the above update options enables
the associated option state and enables the Save Fixed File edit
box. Once you have
selected the option(s) you wish to update, just select the new flag
state that you wish to update in the stream, enter or browse the Save
Fixed File that will save the original file including the new fixes,
and depress the Decode Run button. Depressing the Monitor
Disable button in the center of the tool bar menu will speed up the
Stream header replacement using the WorkShop SDK
The Expert WorkShop SDK can be used update
headers in existing MPEG file using the SDK’s decode section. The decode fix options,
analogous to the GUI options, are set in the ExpDecFix_str structure
in VidDecodeParams_struc structure presented in the ExpDecodeConfigure
API call. Once the fixed items, fixed item states, and fixed
output file name have been set, a sequence of calls to ExpDecodeNextFrame
will cause the updated stream to be written to the fixed output file.
The Decode Fix operation can be used to set or clear the following
The Decode Fix operation can be used to modify the following header
Pan and Scan frame size
The Decode Fix operation can be used to reset
ALL of the time code stamps in the elementary GOP headers. You can enter the time
code of the first frame in the fix options and select the drop_frame
option if needed. The Decode Fix will calculate the appropriate
time codes for all of the GOP headers and replace the existing time
code with this newly calculated time code.
The Decode Fix can be use to add user_data
containing CGMS and APS flags as extended user data. This
user data is added throughout the stream at 2 second intervals.
The Decode Fix can also be used to add Pan
and Scan frame offsets at each frame and/or closed
at selected frames.
Refer to the MPEGRepairHD users manual or the Expert WorkShop SDK manual
for additional details on the updateable headers.
and ExpertWorkshop SDK are trademarks of PixelTools Corporation.
All other brand names are trademarks or registered trademarks of
their respected holders
©1998-2009 PixelTools Corporation