On Sat, Mar 02, 2019 at 01:23:17PM +0800, Yukun Guo wrote: > On Fri, 1 Mar 2019 at 05:30, Michael Niedermayer wrote: > > When data is missing (in live streaming or otherwise) it under > > almost all cases cannot be losslessly recovered. So this use matches > > the definition > > Yes, this is reasonable. But then "Frame num gap" should be of ERROR > level too. H.264 standard states if there is a frame num gap, the > decoder should infer an unintentional loss of pictures, assuming > gaps_in_frame_num_value_allowed_flag = 0. But it is possible that > FFmpeg encounters a frame loss but does not print any error messages, > because the error concealment procedure > (https://github.com/FFmpeg/FFmpeg/blob/n4.1.1/libavcodec/h264_slice.c#L1577) > will clone the previous frame in place of the missing one.
Yes, if this ends up not printing anything then that would be unexpected > > Also, regarding to the error concealment, why isn't > `short_ref[0].field_poc` copied for cloned frames? The unset field_poc > causes "co located POCs unavailable" error, despite > `ref_list[1][0].poc` is valid when doing spatial direct predition. If the frame is copied, its copy would be at a different point in time so it may need a different poc and simply copying it might cause issues thanks [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Take away the freedom of one citizen and you will be jailed, take away the freedom of all citizens and you will be congratulated by your peers in Parliament.
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