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Message: <blockquote data-quote="mm1352000" data-source="post: 695717" data-attributes="member: 82144">[USER=109162]Blue Energy[/USER]: You've got things mostly right there, but here is a fuller explanation...Generally speaking, to display an analog TV channel in MediaPortal the incoming TV signals have to be digitally encoded. Many analog TV cards have hardware encoders to do this. This includes the HDPVR. The HDPVR is somewhat unique in that it encodes into h.264 rather than MPEG 2. Encoding into MPEG 2 in real time can be done in software by most relatively modern high end computers (this is what is done for tuners that don't have hardware encoders). The results aren't necessarily as good as those that would be produced by a hardware encoder, but the point is that it can be done. Encoding to h.264 is a different story. Most high end computers just aren't fast enough (yet <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite2" alt=";)" title="Wink    ;)" loading="lazy" data-shortname=";)" />) to use software encoders to encode h.264 with decent quality in real time. If there is a problem at this stage then you'll possibly see video corruption, stuttering, dropped frames, video-audio sync drift etc.Anyhow, once the TV signal has been digitally encoded, TV Server is responsible for writing the resulting stream to your HDD for timeshifting and/or recording. That requires almost no processing power, but of course the HDD must be fast enough to write the data that is being thrown at it, along with the data coming from any other applications that are running at the same time. Many people use dedicated HDDs (or even RAM drives) for timeshifting/recording to ensure that the HDD has the best chance possible of keeping up with the stream. Most 7200rpm drives shouldn't have any trouble. To give you an indication, I was recording 3 1080i streams just last night without a hitch <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile    :)" loading="lazy" data-shortname=":)" />D). If the HDD is highly fragmented (free space is not continuous => the drive has to move the write head more) or the spindle speed is slower (eg. 5400rpm "green" drives) then there is more chance that the HDD won't keep up. If there is a problem here then you'll also see corruption, stuttering, dropped frames, jitter etc.MediaPortal is responsible for taking the contents of the timeshift file or recording and "playing" it. This requires the digital stream (video + audio) to be decoded, and that is where codecs come in. Codecs are small pieces of software that know how to decode one or more specific media formats (for example MPEG 2 video, AAC, h.264, MP3). MediaPortal builds what is called a graph to connect the timeshift file to the video and audio renders (whose job it is to display the video on screen and pass the audio to the soundcard) with the codecs that you choose to use in MediaPortal configuration. Many people seem to have codec trouble. Often it is because they choose the wrong codecs for the job - codecs that can't work together, can't be used by MediaPortal (not compatible for whatever reason), don't support the required media types, or don't support particular elements of the digital stream that you're trying to watch (this is about how the encoders did things when they created the stream). All of these problems are generally grouped together and called "codec compatibility issues". If you have a problem here then you'll see dropped frames, stuttering, no video, no audio, video-audio sync problems etc.The intensive part of the decoding process is handled by the codecs. They usually use the CPU's processing power, however some newer video codecs (eg. Cyberlink) are able to use the video card. This is what is known as hardware acceleration. It only works if both the video codec and the video card support it. If it works, it can greatly reduce the load on your CPU, freeing it up to do other things. Of course the load doesn't just go away; it gets shifted onto the GPU, which has dedicated hardware that does the job more efficiently. There *usually* isn't a problem with hardware acceleration - it either works or it doesn't...The rest of the decoding is just passing the stream around, and that has to happen in a timely fashion. The stream has to go from the HDD into memory for decoding, and then from memory into the video/audio buffer for display/playback. The biggest potential failure here is the HDD - it has to read the stream at real-time speed. This is usually much easier than writing in real-time, however the same caveats as for creating the timeshift/recording file apply (other applications using the HDD, 5400rpm spindle speed etc.).Hope that aids understanding <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile    :)" loading="lazy" data-shortname=":)" /></blockquote>

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