[FFmpeg-user] Number of frames decoded not = number of frames encoded

Gyan ffmpeg at gyani.pro
Fri Nov 22 21:29:06 EET 2019

On 22-11-2019 07:23 pm, Carl Eugen Hoyos wrote:
>> Am 22.11.2019 um 13:01 schrieb <hydra3333 at gmail.com> <hydra3333 at gmail.com>:
>> time=00:00:04.44 bitrate=1889.4kbits/s dup=25 drop=0 speed= 8.7x
> Audio and video do not have identical start times in your input file (this is normal for transport streams). Our mov muxer does not support variable frame rate, therefore frames have to be duplicated in the output to achieve A/V sync.

Are we looking at the same log? There's no audio being output. Only one 
video stream. But that brings us to the culprit. The MOV muxer does 
default to CFR mode but ffmpeg switches to VSCFR mode when there's only 
one video stream being output with a non-zero first pts, In this mode, 
the gap at the head of the stream will be filled.

Maybe the switch to vscfr shouldn't be automatic and instead be 


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