On Wed, 23 Mar 2016 21:36:35 +0100 Michael Niedermayer <mich...@niedermayer.cc> wrote:
> On Wed, Mar 23, 2016 at 08:44:41PM +0100, wm4 wrote: > > On Wed, 23 Mar 2016 18:37:25 +0100 > > Michael Niedermayer <mich...@niedermayer.cc> wrote: > > > > > On Wed, Mar 23, 2016 at 06:06:37PM +0100, wm4 wrote: > > > > On Wed, 23 Mar 2016 17:51:11 +0100 > > > > Michael Niedermayer <mich...@niedermayer.cc> wrote: > > > > > > > > > On Wed, Mar 23, 2016 at 02:02:11PM +0100, wm4 wrote: > > > > > > It's not practical to keep this with the new decode API. > > > > > > --- > > > > > > ffmpeg.c | 7 ------- > > > > > > ffmpeg.h | 1 - > > > > > > 2 files changed, 8 deletions(-) > > > > > > > > > > its not practical in ffmpeg.c but libavcodec should be able to easily > > > > > check that a decoder which doesnt declare AV_CODEC_CAP_SUBFRAMES > > > > > doesnt decode "subframes" > > > > > Can you move this check into libavcodec ? > > > > > i think otherwise nothing would be checking for missing > > > > > AV_CODEC_CAP_SUBFRAMES anymore > > > > > > > > > > > > > What's the point of this check? > > > > > > to keep track of / detect the cases that put multiple decodable frames > > > in a packet. > > > > > > Whats the point of that? > > > there where several IIRC > > > one is that when too many frames are put in a packet > > > latency increases, another is that seeking granularity is worse > > > (if its not even one packet for the whole file ...) > > > > It's true that too many frames in a packet isn't ideal, but that's not > > what the code checks. > > > > It checks if an audio decoder not marked with AV_CODEC_CAP_SUBFRAMES > > consumes partial packets. > > yes, but a check that checks "if a decoder not marked with > AV_CODEC_CAP_SUBFRAMES consumes partial packets". Is a simple and > zero overhead way of detecting some (not all) cases where there are > multiple frames in a packet. One cant look at a sequence of bytes > that could be any arbitrary format/codec and say > "thats more than 1 frame" it requires codec specific code, > the decoders already do what is needed for some cases, for the others > there is (please correct me if iam wrong which might be) no easy > way except maybe running the parser if one exists over it but that > would not be zero overhead > > > > That might be useful as debug check in > > libavcodec or so, or by properly reviewing patches for new decoders. > > Iam not sure if i understand what you mean exactly but this somehow > sounds like an implication that people would not review patches > properly. > Thats a serious accusation if thats what was meant. Either there is > a problem then it should be pointed to very specifically so it can be > solved or such implications shouldnt be made at all. Well, I'm not sure what else this check is useful for. A new audio decoder will need explicit code to handle multiframe audio by returning the exact number of bytes parsed, instead of e.g. "return avpkt->size;". So it should be pretty obvious whether a decoder does this? Anyway, I could move this check to avcodec_decode_audio4(), would that be ok? > > also replacing automated tests by manual tests is not a good idea It's not really a fully automated test, as FATE doesn't catch these cases at all. It just assumes that (1) the developer is using ffmpeg.c, and (2) actually sees the message. > cpu time is a lot more available than man hours, and even where > a human checks things, having the computer double check it even if > only partial is a overal win, humans make mistakes and can miss/forget > things even if they try their best with the resources available to > them. > > [...] _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
