[FFmpeg-user] Tips on compressing videos created by GoPro

[Andrey Goreev]

Carl,

Thank you for your comments.
Can the option "-pix_fmt yuv420p" be harmful for my files?
I mean does it make outputs any worse if I watch them in a modern player 
such as VLC? 


On Thursday, October 19, 2017 4:28:15 PM MDT, Carl Eugen Hoyos wrote:
> 2017-10-19 16:26 GMT+02:00 Kieran O Leary <kieran.o.leary at gmail.com>:
>> Hi,
>> 
>> On Thu, Oct 19, 2017 at 2:33 PM, Andrey Goreev <aegoreev at gmail.com> wrote:
>
>>> ffmpeg -i [INPUT-FILE]  -y -f mp4 -c:a libfdk_aac -b:a 192k -c:v libx264
>>> -crf 23 -preset slow -map_metadata 0 [OUTPUT-FILE]
>>> 
>> 
>> On a side note: I think the internal ffmpeg aac encoder might as good
>> if not better now than libfsk_aac
>
> I don't think this is correct, at least nobody has provided any
> proof for such a claim.
> (Very credible claim for the opposite exists.)
>
> Maybe you are mixing up libfdk and libfaac?
>
> [...]
>
>>> FFmpeg:
>>> "No pixel format specified, yuvj420p for H.264 encoding chosen.
>>> Use -pix_fmt yuv420p for compatibility with outdated media players.  "
>
> Just to clarify (Kieran's explanation is correct):
> Some ("outdated") players will simply ignore that your file is
> full scale and will show it with incorrect colours.
>
> Note that the warning does not appear with current FFmpeg,
> but the facts remain.
>
> Carl Eugen

-- 
Thanks,
Andrey