[Koying]

This has ever been the case.

Interesting... All the non-ffmpeg codecs I've seen always considered it as a state

PS To be completely clear, does it mean that the next picture should be dropped, whatever the cycle, or that, if there is a picture in next cycle, it should be dropped?

[FernetMenta]

Decoder can drop any frame in the queue but it should report the correct pts when player calls GetCodecStats. Assume player request a drop and decoder drops the 10th frame in the queue. It will take a while for this action to be visible at render stage. Player does account for this delay but need to know the correct pts to do so.

If DVD_CODEC_CTRL_DROP is set on iFlags, decoder should either drop this particular frame or set DVP_FLAG_DROPPED on this frame. This is primarily used for accurate seeks.

[Koying]

Mmm... DVD_CODEC_CTRL_DROP *is* new, isn't it?
As a matter of fact, looks like ffmpeg is the only one implementing it.

What the relation between DVD_CODEC_CTRL_DROP and SetDropState?

PS: At first sight, they do the same.

And SetDropState would do what you describe in the codec BUT the pts would be wrong. Will fix...

[FernetMenta]

DVD_CODEC_CTRL_DROP is mandatory, this frame must not be rendered. Hence drop or set dropped flag. Assume we want to seek to a frame somewhere past next i-frame. We need to decode to this frame but don't want to show any frame prior to the desired one.

SetDropState is a request if possible. There are codecs that don't support dropping of non-ref frames. In this case output stage will skip frames. Less efficient than dropping in decoder.