VPx alt-refs are output as packets which lack timestmps or durations, since they are invisible. Currently, the timestamp mangling code in libavformat will sometimes add a bogus timestamp and duration, if the webm in question has the block duration set (which is a hack, and not really a frame duration at all). In the future, libav* will only output packets without timestamps or duration, so we need to handle it here, regardless. This does not handle NVOPs. We set the duration based on the last PTS, for these packets, because FFMS2 currently sorts packets by PTS, which will break decoding, otherwise.
VPx alt-refs are output as packets which lack timestmps or durations, since they are invisible. Currently, the timestamp mangling code in libavformat will sometimes add a bogus timestamp and duration, if the webm in question has the block duration set (which is a hack, and not really a frame duration at all). In the future, libav* will only output packets without timestamps or duration, so we need to handle it here, regardless. This does not handle NVOPs. We set the duration based on the last PTS, for these packets, because FFMS2 currently sorts packets by PTS, which will break decoding, otherwise.
(ノ°Д°）ノ︵