CFULLHDMA: Trying to understand decoding H.264

During the development of the CFULLHDMA I am always trying the best out of things. (= chipset + firmware). Knowing that not everything can be supported it is always a challenge to get the best.

Therefore my search for answers ..

Challenging the Sigma Designs 8635 chipset is one of the main things I like, especially as we know that the SDK of Sigma Designs is far from perfect.

SD 8635 does not support MKV, so this is added by a lot of manufactures themselves. The chip is strong in TS and MP4 .. 

We did some tests and got feedback from users: some certain files could not be played correct: during playback a lot of artefacts (squares) could be seen. In search for ansers why this happened a lot of debugging and research has been done.

In general this is what is happening: the filestream is forced to be played at H.264 High Profile @ L4.1 but the stream is a High Profile @ L5.x one and this is causing the artefacts.

The H.264 High Profile L5.x does need much more memory than the profile L4.1 (Blueray and HDDVD do use L4.1) ..  Also the ref frames have a role in this part: the more ref. frames, the more issues can be expected.

So in search for solutions it’s being checked if enough power/memory can be made available to decode the H.264 High profile L5.x

So my first suggestion is to remux the stream from L5.x to L4.x and check the amount of ref. frames.

It’s also wise to check some forums. I think the L4.1 is the profile to choose.

note: I am not H.264 expert, so if someone has more info about difference between L4.x and L5.x: please give me some hints

3 thoughts on “CFULLHDMA: Trying to understand decoding H.264

  1. jice says:

    Difference between L 4.x and L 5.x is the Algorithm used for encoding movie. L 5.x is “high profil” and is harder to decompress but it has a better quality for the same file size.

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