Author Topic: "Flashing sequence of pictures" instead of smooth video resulted...  (Read 861 times)

eumagga0x2a

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Re: "Flashing sequence of pictures" instead of smooth video resulted...
« Reply #15 on: May 22, 2018, 07:02:14 PM »
Thanks, we are on it at the moment, don't think that we need new samples. Currently, the problem looks like a ffmpeg bug, there is a workaround as the last resort.

The stream is field-encoded, which is very uncommon nowadays. When the keyframe (the first field) is fed to lavcodec after decoder flush, it immediately pops out a bogus gray image instead of waiting for the second field.
« Last Edit: May 22, 2018, 07:18:29 PM by eumagga0x2a »

EFuggerth

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Re: "Flashing sequence of pictures" instead of smooth video resulted...
« Reply #16 on: May 22, 2018, 07:28:01 PM »
While embracing the good news, I beg of Lord this bug not to escalate into buggery.
« Last Edit: May 22, 2018, 07:30:46 PM by EFuggerth »

eumagga0x2a

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Re: "Flashing sequence of pictures" instead of smooth video resulted...
« Reply #17 on: May 24, 2018, 07:17:59 PM »
Mean has independently found the solution and then identified the upstream fix for FFmpeg which solves this issue and pushed the changes necessary to integrate this patch into Avidemux. You might want to try the latest nightly (r180524 at the moment). Please be aware that you won't be able to save a similar field-encoded mpeg2 video in copy mode yet.
« Last Edit: May 24, 2018, 07:22:48 PM by eumagga0x2a »

EFuggerth

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Re: "Flashing sequence of pictures" instead of smooth video resulted...
« Reply #18 on: May 31, 2018, 04:35:17 PM »
This Mean-news is happy-news, rather.
(Sorry for my being late with checking your newest “nightly”.)
Full visibility on tracking the frames is restored, indeed. (So, manipulations can now be followed again.)
HOWEVER: The complete (cut) film [if it comes from appending and saving the Avidemux-manipulated segments of the fixed broadcast] (on the usual “VLC” replay) exhibits a marked, extremely disturbing asynchrony between pictures and voices. [N.B.: the saving-process of the appended parts onto a single-part film is unusually slow.] On the contrary: No such asynchrony emerges if the resulting film is made by appending the original segments first and then Avidemux-manipulating the whole [and saving it (in an output format “Mpeg2 TS muxer (ff)”)]. (Wherefore, incorporating a direction running this way into your next nightly could be useful.)
This I experienced after several trials.
How further then?
Your last sentence in the latest message warns as “Please be aware that you won't be able to save a similar field-encoded mpeg2 video in copy mode yet.” Does it mean I should be expecting some further refining?

eumagga0x2a

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Re: "Flashing sequence of pictures" instead of smooth video resulted...
« Reply #19 on: May 31, 2018, 10:56:36 PM »
As stated above, the copy mode for field-encoded video is broken. Fix upcoming.

Re-encoding (adding a good deinterlacer is highly recommended) should work.