On Mon, Jun 17, 2024 at 8:29 PM Mark Filipak <markfilipak.i...@gmail.com> wrote:
> On 17/06/2024 13.50, Paul B Mahol wrote: > > On Mon, Jun 17, 2024 at 5:35 PM Mark Filipak <markfilipak.i...@gmail.com > > > > wrote: > > > >> On 17/06/2024 03.16, Paul B Mahol wrote: > >>> On Mon, Jun 17, 2024 at 3:16 AM Mark Filipak < > markfilipak.i...@gmail.com > >>> > >>> wrote: > >>> > >>>> To expand on my idea: > >>>> > >>>> The video is this: > >>>> I P B B P B B P B B I P B B.. > >>>> I want to change it to this: > >>>> I B B P B B P B B P I B B P.. > >>>> > >>> > >>> If this is what I think it is, your are wasting your time. > >> > >> It is possible. But can FFmpeg do it? You see, Paul, I read in several > >> places from seemingly > >> authoritative people that professional videos are PTS-ordered. I've > since > >> discovered that > >> professional videos are almost always DTS-ordered -- I now have a packet > >> browser and have seen it to > >> be true. However, I have seen professional videos that are PTS-ordered > but > >> I didn't think too much > >> about it at the time. > > > > PTS order is order once frames are decoded and going to be presented to > > user, thats why it is called presentation timestamps. > > Yes of course. > > >> My idea is to take the 4-second video -- DTS-ordered -- that I sent to > >> trac, change it to > >> PTS-ordered, and see if '-vf showinfo' and '-f show_frames' respond > >> correctly. It's a long shot, but > >> it might show something useful -- what if PTS-order made showinfo > >> show_frames and framecrc all > >> agree? Wouldn't that be something interesting? > > > > If decoder follows specifications for decoding bitstreams correctly than > > changing order of raw encoded frames as stored in bitstream will almost > > every-time cause broken decoding. > > > >>> Its nonsense to change order of encoded frames, no manipulation of > clock > >>> can fix that. > >> > >> No, no. Manipulation of PCR. Fix up the PCRs so that the result is truly > >> PTS-ordered. > > > > If this is at format container layer, I dunno how would that work even if > > its is possible to be useful. > > The container would contain a PES packet stream with PCRs like any other > PES packet stream. It would > work like any PTS-ordered stream does. You know, there _are_ PTS-ordered > streams. And you know, MPEG > is silent on the matter of what physical order frames are in the stream, > only that they must be > given to the decoder in DTS-order. > > Look, I agree that it would be nonsense. I want to turn the DTS-ordered > stream into a PTS-ordered > stream merely as a test: '-f show_frames' appears to be getting DTSes and > PTSes mixed up, then > applying a fix that results in completely new DTSes. If it treats the > PTS-ordered stream > differently, that will say a lot. What is says depends on what it does. > Capiche? > > I thought I could do it by demuxing, then moving them like you can move > frames in a filter_complex, > and then remuxing, but I don't know how to do that to PES packets (instead > of decoded pictures) and > I don't know how to rewrite PCRs. > But aren't you working with HEVC and not MPEG video? > _______________________________________________ > ffmpeg-user mailing list > ffmpeg-user@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email > ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe". > _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".