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

serialhex serialhex at gmail.com
Thu Jan 25 16:09:41 EET 2018

On Thu, Jan 25, 2018 at 8:07 AM, DopeLabs <dopelabs at dubstep.fm> wrote:

> have you tried different players such as ffplay, mpv, IINA, mplayer?

I have tried different players.  VLC, the Ubuntu player and the Kodi player
on my Pi don't work.  ffplay & Chrome both work.

> have you tried a different encapsulation such as .mp4 or .flv or .mov?

I would love it if I could do this reliably, but  the subtitles often don't
transfer, and the same with multiple audio streams (I usually like subs,
but sometimes the dubs are really good).
I thought I could do WEBM as it's essentially a MKV with specific video,
audio & subtitle codecs, but as far as I've been able to tell, there is no
player that accepts the WEBM subtitle codec... :'(

looking at your console output..
> keyint=250
> maybe try and have those more often?
> or maybe try and pad the beginning with a few black frames?

I have tried adding keyframes to the beginning, but I haven't tried this,
adding it to the list of things to try...

> if it works 99% of the time does that mean videos seem to faile 1% of the
> time at random? or can you try again and it will work properly?

It doesn't matter how many times I re-encode a file, the same file will
always fail.  I've tried making *just* a video from the image sequence and
that works, but once I add the audio & subtitles it breaks.
I've even tried letting it choose my codecs by removing the `-codec copy`
part of my command line (the h264 video needs to stay because my I know my
Pi will play that).  Same result.

I'm almost to the point of hitting up the ffmpeg developers list and filing
this as a bug... I'm seriously at a loss as to what to do.
It's just so weird that taking the same clip and encoding only 10 seconds
of it works, but encoding 20 seconds breaks... :-/ And whole episodes break

Maybe, is there a way to extract all of the streams in a file to a bunch of
separate files without reencoding them, and then assemble them back
together? Basically to get rid of the original file completely?

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