[FFmpeg-user] Reencoding video from image sequence doesn't work (sometimes)

serialhex at gmail.com serialhex at gmail.com
Tue Jan 23 19:54:49 EET 2018

DopeLabs wrote
> once you have your image sequence, encoding them into a movie should be
> pretty straight forward.

And that's the rub.  It *is* straightforward, and what I'm trying to do
works on 99% of my videos, but for some reason, there are a handful of
videos where the picture DOES NOT START when the rest of the video does. 
Audio starts, and subtitles might, but the picture DOES NOT.

Fastforwarding the video to some arbitrary point and then rewinding to NEAR
the beginning works, but if you rewind ALL THE WAY to the beginning whatever
WAS on the screen just stays there and never updates.

One of the things I just realized is playing the video all the way through
the picture eventually comes in, and I get messages like this:

  Stream #1:1 -> #0:1 (aac (native) -> vorbis (libvorbis))
  Stream #1:2 -> #0:2 (ass (ssa) -> ass (ssa))
  Stream #1:3 -> #0:3 (copy)
Press [q] to stop, [?] for help
[image2 @ 00000000002da3e0] Thread message queue blocking; consider raising
the thread_queue_size option (current value: 8)
[matroska @ 00000000032254a0] Starting new cluster due to timestamp= 
93.4kbits/s speed=11.2x
[matroska @ 00000000032254a0] Starting new cluster due to timestamp=
963.1kbits/s speed=2.19x
frame=26853 fps= 40 q=-1.0 Lsize=  179749kB time=00:23:20.00
bitrate=1051.8kbits/s speed=2.06x
video:162698kB audio:16217kB subtitle:21kB other streams:0kB global
headers:6kB muxing overhead: 0.454852%
[libx264 @ 00000000031c98e0] frame I:638   Avg QP:18.35  size: 41747

What's up with the "Starting new cluster due to timestamp= ..." thing?  It
doesn't record the actual timestamp in the output later, but I recall it did
that saying it was at about 2 minutes, and at about 2 minutes in the picture
appears (which doesn't seem to help on my Raspberry Pi at all).

Also, this problem only seems to happen on *some* players.  Since VLC is the
only thing that really plays MKV files, it's the only thing I can use to
test, but while VLC doesn't play these files from the beginning, Chrome
seems to work just fine.  Again, my this doesn't help on my Pi.

Recently I've tried to not just copy everything except the picture, but
reencode everything.  This didn't work either.

Thanks for any further help.

Carl Eugen wrote
> I assume you tested that this is better than FFmpeg's (old)
> super2xsai filter. Is it also better than FFmpeg's hqx filter?
> (You agree that faster alone doesn't really help if you have
> to reencode twice, no?)

I checked this out after you recommended it, and it doesn't do nearly as
good a job as my super-long 2+ hour encoding process makes my crappy
TV-quality videos into damn-near HD-quality videos.  Thanks for the
suggestion though. 

Sent from: http://www.ffmpeg-archive.org/

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