[FFmpeg-user] Confusion about pix_fmt

[Michael Heuberger]

Hello guys

If you look at the bug report at https://trac.ffmpeg.org/ticket/4098 you
can see that I am confused about the pix_fmt option.

I am not sure what parameter to use for this option. All I want is to
make the video compatible on *modern* browsers/players only and I also
want to make the warning disappear ffmpeg is generating:

deprecated pixel format used, make sure you did set range correctly

This warning led me to believe I have to set a different pix_fmt
parameter than the default one (yuv420p). But I do not know which one.

Any clues?

Michael
--
Binary Kitchen
Michael Heuberger
4c Dunbar Road
Mt Eden
Auckland 1024
(New Zealand)

Mobile (text only) ... [phone]
Email ................ ***@binarykitchen.com
Website .............. http://www.binarykitchen.com

[James Darnley]

Post by Michael Heuberger
Hello guys
If you look at the bug report at https://trac.ffmpeg.org/ticket/4098 you
can see that I am confused about the pix_fmt option.
I am not sure what parameter to use for this option. All I want is to
make the video compatible on *modern* browsers/players only and I also
deprecated pixel format used, make sure you did set range correctly
This warning led me to believe I have to set a different pix_fmt
parameter than the default one (yuv420p). But I do not know which one.
Any clues?
Michael

yuvj420p and yuv420p are the same. If a video player can play one it
can play the other.

The "j" refers to the range of values that are output. "j" is full
range (or PC range) meaning it uses all 0-255 values rather than the
more common 16-235 range (which is known as TV or Studio range).

The problem comes when converting to RGB on playback. All good players
recognize a flag in the file indicating that it is full range and
convert it properly. All bad players do not. They assume it is TV
range and expand the range of values causing too high contrast which is
noticeable. Another similar symptom is players that do not expand the
range when they should leading to too low contrast.

I do not know whether browsers fall into the good category. If you want
a correct picture on every possible system use yuv420p.

If you want to know more about the colour space and this "j" option I
suggest you read these:
https://en.wikipedia.org/wiki/YCbCr
https://en.wikipedia.org/wiki/YCbCr#JPEG_conversion

[Carl Eugen Hoyos]

All I want is to make the video compatible on *modern*
browsers/players

Then you have to use "-pix_fmt yuv420p" which is
different from "yuvj420p" and I believe "good players"
are rare.

I also want to make the warning disappear ffmpeg is

As said, this is not possible: The warning appears if
either the input or the output pix_fmt are yuvj*-

Carl Eugen

[Michael Heuberger]

Thank you guys! - Learning here ...

Post by Carl Eugen Hoyos

All I want is to make the video compatible on *modern*
browsers/players

Then you have to use "-pix_fmt yuv420p" which is
different from "yuvj420p" and I believe "good players"
are rare.

I also want to make the warning disappear ffmpeg is

As said, this is not possible: The warning appears if
either the input or the output pix_fmt are yuvj*-
Carl Eugen
_______________________________________________
ffmpeg-user mailing list
http://ffmpeg.org/mailman/listinfo/ffmpeg-user

--
Binary Kitchen
Michael Heuberger
4c Dunbar Road
Mt Eden
Auckland 1024
(New Zealand)

Mobile (text only) ... [phone]
Email ................ ***@binarykitchen.com
Website .............. http://www.binarykitchen.com