[FFmpeg-user] Question about 2 pass encoding

[Aditya Dandavate]

Okay, fine.

But according to H.264 guide :

Warning: When using option -an, you may eventually get a segfault or a
broken file. If so, remove option -an and replace by -vsync cfr to the
first pass.

When I put `vsync cfr` then it says that `-vsync` is deprecated, use
`-fps_mode`

What is all this happening ?

On Mon, 1 Apr, 2024, 8:01 pm Srikanth Kotagiri, <srikanthk at gmail.com> wrote:

> On Mon, Apr 1, 2024 at 3:40 AM Aditya Dandavate
> <adityadandavate04 at gmail.com> wrote:
> >
> > and then
> >
> > ffmpeg -y -i Capture.mp4 -pix_fmt yuv420p -c:v libx264 -pass 1 -an
> > -b:v 2600k -f mp4 NUL
> >
> > ffmpeg -y -i Capture.mp4 -pix_fmt yuv420p -c:v libx264 -pass 2 -an
> > -b:v 2600k myVideo.mp4
> >
> >
> > Source :
> >
> >
> https://video.stackexchange.com/questions/21953/ffmpeg-error-2nd-pass-has-more-frames-than-1st-pass
> >
> >
> > Can I use `-c:a` copy for audio codec instead of `-an` for both passes ?
> > _______________________________________________
> > ffmpeg-user mailing list
>
> When you run the first pass command, you are creating a "stats file".
> Notice the -f mp4 NUL, there is no actual media output being created.
> Adding -c:a copy or any actual codec is a waste of IO. You can include
> -c:a copy in the second pass where you are actually creating an output
> file.
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