How to debug H264 DirectShow filter?

Question

I'm developping a h264 directshow filter.

I have a valid hardware source which outputs NAL units properly. I have a DirectShow filter which advertises h264 and successfully connects to the default windows 7 decoder microsoft dtv-dvd video decoder.

When I connect a renderer to the decoder, the renderer doesn't get any packets, so I assume that the decoder fails to decode my packets properly.

[ h264 Source ] -> [ dtv-dvd decoder ] -> [ enhanced video renderer ]

Is there any way for me to check where the microsoft decoder fails?

Any other info could be helpful

Answer 1

The difficulty you have is that you do not have the code for the dtv-dvd decoder, making it somewhat of a black-box in the pipeline. The fact that your h264 Source can connect to the dtv-dvd decoder means you are off to a good start regarding media format negotiation. To get a better view of what is going wrong I suggest that you swap out the dtv-dvd decoder with one for which you have the source code and then debug your pipeline using GraphEdit or one of the similar tools. I have been doing the same sort of development and have found that once I got the h264 pipeline working properly with one decoder filter, it has generally worked properly with other h264 decoders.

Here are a few options which include source code:

• Intel Media SDK 2012 includes a sample h264 decoder filter.

• If you have an Nvidia GPU, you can try out this open source CUDA Decode Filter

Also, I have found the dtv-dvd filter to be a little finicky. It may be helpful to test using one of the following decoder filters available in binary form :

• Nanocosmos has a very nice "AVC/h264 decoder Decoder SDK" based on directshow. (Free Eval)

• "CoreCodec's CoreAVC" includes one of the fastest h264 decoders supporting CUDA and DXVA (Commercial - costs $12.95)

• MainConcept's h264 decoder filter is available as part of their "MainConcept Showcase" (Free Eval)