Regd buffer management in multimedia filters

QNX DEVELOPERS Porting
1

Hi,

We have a multimedia graph which has reader, parser, decoder and writer connected in the same order.

Reader used: stream_reader.so (Qnx provided)
Parser used: mp3_parser.so ( implemented by us)
Decoder used: mp3_decoder.so ( implemented by us)
Writer used: audio_writer.so (Qnx provided)

We are able to create the graph. When we start playing the graph using Mmplay(), only one buffer is passed from parser->decoder->writer to write the pcm samples into the H/W.

Could you Please us in understanding how the control flow is from the writer to the other filters in the graph.

From the documentation, v can refer the below.
Writer will call the decoder’s NextBuffer(). Writer is calling it only for the first time. Afterwards, it is not calling.

Thanks in advance.

2

Writer is calling its previous filter’s NextBuffer only if media buffer allocator is properly done and the Flags of the Mmbuffer_t is properly set. (MM_BUFFER_KEYFRAME).