Hi, really sorry about the very late review on this one (I was out for a while, and then spent a lot of time catching up on review while I was out, and then trying to get some more important Wine work done...)
2/7, seeking parts aside, is broadly doing the right thing (from my perspective) but I would like to see it arranged differently. What I would like to see is something like the following, in a series of individual patches:
* Introduce a wg_parser_create option to use the encoded format; this should end up being translated to "chain_decodebins" basically as you have it. I would also rename that to something like "output_compressed" (with inverted meaning).
Note that in this case autoplug-continue already does what we want, you shouldn't need to set the "caps" property on top of that.
* Use this property, plus WG_PARSER_DECODEBIN, in the existing frontend instead of WG_PARSER_MPEGAUDIOPARSE. Delete WG_PARSER_MPEGAUDIOPARSE.
* Ideally patch 1/7 should be moved from the beginning of the series to here.
* Add MPEG-1 system stream support to the quartz frontend.