Re: [FFmpeg-devel] libavcodec/psd : add support for rgb/gray float

[Martin Vignali]

2017-03-08 2:15 GMT+01:00 Dzung Hoang :

> I implemented a 32-bit float GBRAP/GBRP pixel format and used it in
> vf_zscale.c and vf_overlay.c. I also implemented an EXR encoder using
> miniexr that uses the new float pixel format. I can contribute this if
> there is interest.
> I used the above mods to do HDR video processing that includes overlaying
> HDR and SDR video. IMHO, for ffmpeg to handle HDR video well, float and
> half-float are needed and also metadata to signal the color space and
> transfer function for each picture. It's a big job that can touch a lot of
> code, which is why I kept my changes private and limited to only what I
> need.
>
>
If you already working on this, it can be interesting to post your work on
this mailing list.

I think the integration of float processing, can be made by steps
(input/output pixels formats, exr encoder, integration in filter(s))


Martin
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Re: [FFmpeg-devel] libavcodec/psd : add support for rgb/gray float

[Dzung Hoang]

I implemented a 32-bit float GBRAP/GBRP pixel format and used it in vf_zscale.c 
and vf_overlay.c. I also implemented an EXR encoder using miniexr that uses the 
new float pixel format. I can contribute this if there is interest.
I used the above mods to do HDR video processing that includes overlaying HDR 
and SDR video. IMHO, for ffmpeg to handle HDR video well, float and half-float 
are needed and also metadata to signal the color space and transfer function 
for each picture. It's a big job that can touch a lot of code, which is why I 
kept my changes private and limited to only what I need.


  From: Martin Vignali <martin.vign...@gmail.com>
 To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org> 
 Sent: Tuesday, March 7, 2017 4:16 PM
 Subject: Re: [FFmpeg-devel] libavcodec/psd : add support for rgb/gray float
   
Hello

@Carl :
I make some tests in order to avoid temp buffer, but i have some strange
result, when i not use a temp buffer.


> Time to think about a float pixfmt? I find it weird that we support
> excessively obscure pixfmts like AV_PIX_FMT_BGR4_BYTE, but then have
> hacks like this one if the codec uses float data.
>
> (I'm just commenting, not arguing for/against your actual patch.)
>
I agree with your comment.
Float pixfmt is a more clean way.
it can also be useful for image processing with filters, and encoding float
data.

Any tips to add support for float pixfmts ?
I try to take a look to the source code, but it's not very easy to
understand.

Martin
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Re: [FFmpeg-devel] libavcodec/psd : add support for rgb/gray float

[Martin Vignali]

Hello

@Carl :
I make some tests in order to avoid temp buffer, but i have some strange
result, when i not use a temp buffer.


> Time to think about a float pixfmt? I find it weird that we support
> excessively obscure pixfmts like AV_PIX_FMT_BGR4_BYTE, but then have
> hacks like this one if the codec uses float data.
>
> (I'm just commenting, not arguing for/against your actual patch.)
>
I agree with your comment.
Float pixfmt is a more clean way.
it can also be useful for image processing with filters, and encoding float
data.

Any tips to add support for float pixfmts ?
I try to take a look to the source code, but it's not very easy to
understand.

Martin
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Re: [FFmpeg-devel] libavcodec/psd : add support for rgb/gray float

[wm4]

On Wed, 1 Mar 2017 23:42:28 +0100
Martin Vignali  wrote:

> Hello,
> 
> In attach patch for decoding float data (rgb/gray only) inside psd
> Like in the openexr decoder, float data is convert to uint16
> A gamma conversion can be apply before uint16 conversion (with an option)
> 
> the function : static inline uint16_t psd_flt2uint(uint32_t v)
> is a copy/paste of exr_flt_uint of the exr decoder.
> Probably need to be move somewhere (but i don't know the best place for that)
> 
> Sample can be found here :
> https://we.tl/85kvceapTL

Time to think about a float pixfmt? I find it weird that we support
excessively obscure pixfmts like AV_PIX_FMT_BGR4_BYTE, but then have
hacks like this one if the codec uses float data.

(I'm just commenting, not arguing for/against your actual patch.)
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Re: [FFmpeg-devel] libavcodec/psd : add support for rgb/gray float

[Carl Eugen Hoyos]

2017-03-01 23:42 GMT+01:00 Martin Vignali :
> Hello,
>
> In attach patch for decoding float data (rgb/gray only) inside psd
> Like in the openexr decoder, float data is convert to uint16
> A gamma conversion can be apply before uint16 conversion (with an option)
>
> the function : static inline uint16_t psd_flt2uint(uint32_t v)
> is a copy/paste of exr_flt_uint of the exr decoder.
> Probably need to be move somewhere (but i don't know the best place for that)

If no other suggestions are made, move it to libavcodec/internal.h
and make it av_always_inline.

Is the buffer always necessary, or can the transformation be done
in-place?

> Sample can be found here :
> https://we.tl/85kvceapTL

Thank you, Carl Eugen
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[FFmpeg-devel] libavcodec/psd : add support for rgb/gray float

[Martin Vignali]

Hello,

In attach patch for decoding float data (rgb/gray only) inside psd
Like in the openexr decoder, float data is convert to uint16
A gamma conversion can be apply before uint16 conversion (with an option)

the function : static inline uint16_t psd_flt2uint(uint32_t v)
is a copy/paste of exr_flt_uint of the exr decoder.
Probably need to be move somewhere (but i don't know the best place for that)

Sample can be found here :
https://we.tl/85kvceapTL


Comments welcome

Martin


0001-libavcodec-psd-add-support-for-rgb-gray-float.patch
Description: Binary data
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