On Sat, Nov 18, 2017 at 09:50:33AM +0100, Hendrik Leppkes wrote: > On Sat, Nov 18, 2017 at 3:05 AM, Michael Niedermayer > <mich...@niedermayer.cc> wrote: > > On Fri, Nov 17, 2017 at 09:55:47AM +0100, Hendrik Leppkes wrote: > >> On Fri, Nov 17, 2017 at 5:00 AM, Michael Niedermayer > >> <mich...@niedermayer.cc> wrote: > >> > On Thu, Nov 16, 2017 at 01:51:34PM +0100, Carl Eugen Hoyos wrote: > >> >> 2017-11-16 13:44 GMT+01:00 Michael Niedermayer <mich...@niedermayer.cc>: > >> >> > On Thu, Nov 16, 2017 at 01:04:27AM +0100, Carl Eugen Hoyos wrote: > >> >> >> 2017-11-15 13:34 GMT+01:00 Michael Niedermayer > >> >> >> <mich...@niedermayer.cc>: > >> >> >> > Hi all > >> >> >> > > >> >> >> > I intend to make 3.4.1 very soon > >> >> >> > >> >> >> Shouldn't we first decide on how to proceed with #6775? > >> >> > > >> >> > This would be ideal. > >> >> > > >> >> > IIUC this is a regression from > >> >> > bddb2343b6e594e312dadb5d21b408702929ae04 > >> >> > >> >> This was confirmed by more than one developer, yes. > >> >> > >> >> > I see a patch that is said to improve 6775, can that be applied and > >> >> > would that resolve this ? > >> >> > >> >> Iiuc, it would not completely resolve the issue, see: > >> >> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=881536 > >> >> > >> >> > If so why was it not applied yet ? > >> >> > >> >> The patch did not get support here, see: > >> >> [FFmpeg-devel] [PATCH] lavc: reset codec on receiving packet after EOF > >> >> in compat_decode > >> > > >> > > >> > Is someone working on fixing this better than with the available patch ? > >> > > >> > >> I don't even agree this needs fixing. Those projects use the API wrong. > > > > Had we documented the correct/wrong use precissely in the past when > > these wrong uses where written ? > > > > Because if it was documented then few should have made the mistake. > > But it seems this affects multiple projects, so i wonder if our API > > really excluded the use > > > > Apparently not well enough, but I also don't even understand why you > would *want* to drain in the middle of decoding. > > The only mention of sending NULL/0 packets (in 3.0 docs, before the > new API was introduced) do include the "at the end", however. > > From CODEC_CAP_DELAY: > * Decoders: > * The decoder has a non-zero delay and needs to be fed with avpkt->data=NULL, > * avpkt->size=0 at the end to get the delayed data until the decoder no > longer > * returns frames. > > From avcodec_decode_video2 > * @note Codecs which have the AV_CODEC_CAP_DELAY capability set have a delay > * between input and output, these need to be fed with avpkt->data=NULL, > * avpkt->size=0 at the end to return the remaining frames. > > There is a few more mentions of the same concept, but as far as I can > see all include the key words "at the end". >
> For the suggested patch, draining and flushing in the middle of a > bitstream is still going to result in problems, though, since it > removes all reference frames, for example. > The original behavior cannot really be stored, which was to just keep > feeding frames into the decoder after a drain without a flush. > However, some decoders actually crashed when you did this, so this was > a rather unsafe action to begin with (not an issue any longer, since > this pattern is now blocked). Did the previous code really work if the frame after a flush was not a new keyframe or there was some use of previous references ? [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB "Nothing to hide" only works if the folks in power share the values of you and everyone you know entirely and always will -- Tom Scott
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