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Software Version
Please check that you have the most recent version of the MPEG System and Program Stream Multiplexer.
| Product | Current Version | Operating System | Release Notes |
|---|---|---|---|
| SPMux | V4.0.0 | Windows, OS X, Linux | spmux-relnotes-4.0.pdf |
We encourage all users to stay up to date with the current version. For upgrade and maintenance agreement information, please contact sales@manzanitasystems.com.
Frequently Asked Questions
Please check to see if your question about out MPEG System and Program Stream Multiplexer (SPMux) is answered here. If your question still has not been answered, please contact our tech support department at support@manzanitasystems.com.
- I am currently using Manzanita's MPSPSM to mux my program streams. How is SPMux different? Will I still be able to use my configuration files?
- Prior to SPMux V3.0, Manzanita's MPEG System and Program Stream Multiplexer product was identified by the acronym MPSPSM. We found SPMux easier to say and a better identifier for the product. SPMux V4.0 is a complete replacement and update for all versions of MPSPSM, and earlier versions of SPMux. Although we've added a GUI and a few new configuration parameters, your configuration files are fully compatible with SPMux and they will produce the same output streams.
- I get underflows when I am multiplexing a video stream, what should I do?
- There are several possible solutions to a video underflow. Several factors must be considered before selecting the best solution. If the underflow occurs early in the stream, for example within the first second, then the problem may be caused by an initial delay that is too small and insufficient data in the decoder buffer. This can be solved with the Delay Parameter by increasing the initial delay to allow more data to enter the decoder's buffer prior to the first picture being decoded. If the error occurs later in the stream and gets progressively worse, then the likely cause is an incorrect bit rate for the stream. In this case the Rate Parameter should be used to increase the bit rate allocated for this stream to eliminate the underflow.
- I get underflows when I am multiplexing an audio stream, what should I do?
- There are several possible solutions to an audio underflow. If the underflow occurs early in the stream, for example within the first second, then the problem may be caused by an initial delay that is too small and insufficient data in the decoder buffer. This can be solved with the Delay Parameter by increasing the initial delay to allow more data to enter the decoder's buffer prior to the first access unit being decoded. If the error occurs later in the stream and gets progressively worse, then the likely cause is an incorrect bit rate for the stream. In this case the Rate Parameter should be used to increase the bit rate allocated for this stream to eliminate the underflow. If the underflow is sporadic, then it may be caused by a large audio packet size. The default audio packet size is 1024 bytes of payload, you should trying smaller packet sizes, such as 512 or 768 bytes to see if this eliminates the underflow. A final possibility is if the audio is AC-3 and at a higher rate. In this case the larger frame sizes may be difficult to deliver to the decoder in time with the standard sized decoder buffer. You should verify the size of your decoder buffer and use the correct size with the DBsize Parameter, or alternatively use the ATSCbuf Parameter to use the ATSC style audio decoder buffer.
- I set the Duration Parameter to 1:00:00:00, but SPMux says the stream that it created is 00:58:30 (hh:mm:ss). Why is the output stream shorter than the duration that was specified?
- The SPMux multiplexer can only create an output stream that is as long as the input elementary stream with the longest duration. So, your output stream will be the length that you desire only if all of your input elementary streams are as long as or longer than the specified duration. In addition, the reported duration may vary by +/- 1 second due to rounding in computing this value.
- I'm muxing an MPEG-1 variable bit rate video stream and the output file is huge, in fact my hard drive fills! What is wrong?
- MPEG-1 variable bit rate (VBR) video streams have the bit rate field set to the max allowable. For MPEG-1 VBR video the Rate Parameter must be specified for the video stream. The value used should be the actual maximum rate that will be encountered in the stream.
- I have a transport stream file that I want to remultiplex as a program stream using SPMux. How can I do this when SPMux only accepts elementary streams as input?
- SPMux includes an integrated Demultiplexer that can be used to demultiplex the video and audio elementary streams from the transport stream file. These elementary streams can then be remultiplexed as a program stream with SPMux.
- I would like to insert Closed Captioning into a program stream. How would I do this?
- If you have don't already have a video elementary stream with embedded closed captioining, you can use the Closed Caption Tool in Manzanita Systems' MP2TSME program to insert the EIA608 or EIA708 data into the video elementary stream. You can then use that video elementary stream in any program stream.