- PowerPoint to MPEG Conversion
MPEGRepairHD can be used to convert any PowerPoint
presentation to an MPEG stream with a user selectable slide duration.
Demo of PowerPoint Conversion
A demonstration of the PowerPoint conversion process
can be obtained by clicking ppt2mpeg.zip.
Download this file, unzip the directory structure and execute the runppt.bat
file. The demo compresses a sample PowerPoint slide sequence
into an MPEG file using the batch process of MPEGRepairHD. The resultant
PixelTools.Mpg can be viewed on any MPEG-2 player.
PowerPoint to MPEG using
the MPEGRepairHD GUI
MPEGRepairHD can encode a sequence of bitmaps of
dimension with patent-pending technique that
instructs MPEG decoders
to display each
bitmap with a specific duration. Click on image to see actual size screen.
The first step is to convert your PowerPoint
presentation into a sequence of bitmap files. Select Edit |
Select All to select your entire presentation. The select File |
Save As | Device Independent Bitmaps and enter the name of the
bitmap to be saved in the Save As dialog box.
The next step is to configure MPEGRepairHD
to encode the sequence with the appropriate duration. An easy
way to do this is to use the PptToMpg.ini in the above referenced
demo. Just depress the
down arrow in the Base Encoding Profile edit box, select the Load Custom
ini file and browse to the PptToMpg.ini configuration file. Browse
to the first slide using the File button in the Encode Input edit box. Browse
or enter the name of the resultant MPEG file in Encode Output edit
box. Depress the Run button to complete the process.
The trick in creating high quality MPEG streams is using the correct
parameters. The parameters require some non-intuitive selections. Some
tips on Optimize Encode | Configure parameter selection:
Number of Frames: Select the total number of source
slides that you wish to convert into an MPEG file. You can also enter
ALL which will encode all slides in the sequence in your source directory.
Bitrate: Select the desired output
bit-rate for your target decoder.
Output Rate:Select: the Output Frame Rate appropriate
for your target decoder. 25, 29.97 or 30 are typical frame rates. Do
not use the frame rates in parenthesis as these are not legal MPEG
Compressed Image Size: Enter the dimensions of your
Enable Stuffing: Check this option to create constant
bit-rate streams. For variable bit-rate decoders, un-checking this
option will create extremely small high quality MPEG files
M: Must be 1 for this mode
Input Control: Select the
Multiply Input Frame Rate By: option and enter your desired
frame rate multiplier in the adjacent edit box to result in your
desired slide duration. For example,
if your frame rate has been set to 30 (frames per second) and you want
each slide to be displayed for 5 seconds, the multiplier should be
30 x 5 or 150.
Audio /Mux: If you wish to create a multiplexed stream
including an audio file, check the appropriate Output Stream
and Audio Source Options. Depress the Mux button
to select your desired multiplexing type and output bit-rate.
PowerPoint to MPEG using the Expert Workshop® SDK
The Expert Workshop SDK can be used to encode a sequence
of bitmaps to be displayed at a slow duration IE several seconds per
Some hints at setting parameters:
VidEncodeParams_struc .frame_rate_code should
be set the actual output frame rate code that your target decoder
runs at in the
VidEncodeParams_struc .M should be set to 1
VidEncodeParams_struc .eNABLESTUFFING should be set
true to create constant bit-rate streams or false for highly compressed
variable bit-rate streams.
VidEncodeInputControl_struc.RateBy should be set
to the number of repeated frames you wish to add to each source bit-map.
For example, if your frame rate has been set to 30 (frames per second)
and you want each slide to be displayed for 5 seconds, the RateBy value
should be 30 x 5 or 150.
To create the MPEG file, call ExpEncodeNextFrame
for the number of source slides. The encoder will add flags that
instruct the decoder
to repeat the current frame for the number of RateBy frames.
Any bitmap file sequence (that has a horizontal size
evenly divisible by 16) created from a Microsoft PowerPoint presentation
can be converted to an MPEG file.
The PixelTools encoder can add null frames as
specified in the Input Control | Multiply Input Frame Rate By value. This
will create a legal MPEG stream whereby the decoder will be instructed
to display each bitmap for an extended length of time.
Disabling the Parameters | Enable Stuffing button will create an amazingly
small MPEG file that is mostly a function of the compressed sizes of the
source bit-maps and not the actual length of the stream.
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