[FFmpeg-devel] [PATCH v2] lavf/qtpalette: Treat 1-bit video as palettized

[Michael Niedermayer]

On Tue, Dec 29, 2015 at 07:38:04AM +0100, Mats Peterson wrote:
> I forgot some stuff. Patch description follows:
> 
> This patch for qtpalette.c and qtpalette.h adds 1-bit video to the
> "palettized video" category, since if the video sample description
> contains a palette, the two colors in the palette can be any color, not
> necessarily black & white.
> 
> Unfortunately, I've noticed that the qtrle (QuickTime Animation) decoder
> blindly assumes that 1-bit video is black & white. I don't have enough
> knowledge about the decoder to fix this, though.
> 
> Below is a link to a sample 1-bit QuickTime Animation clip of a rotating
> earth that uses blueish colors, and they will be correctly rendered in
> QuickTime, but not in FFmpeg (which will use black & white).
> 
> https://drive.google.com/open?id=0B3_pEBoLs0faUlItWm9KaGJSTEE
> 
> Mats
> 
> -- 
> Mats Peterson
> http://matsp888.no-ip.org/~mats/

>  qtpalette.c |    8 +++++---
>  qtpalette.h |    5 +++++
>  2 files changed, 10 insertions(+), 3 deletions(-)
> 6aff88fb703e1d4e0a3412816d376ee0c02be605  0001-lavf-qtpalette-Treat-1-bit-video-as-palettized.patch
> From 64dbe9e1555513d5ba3fc03951711ffb6c51b008 Mon Sep 17 00:00:00 2001
> From: Mats Peterson <matsp888 at yahoo.com>
> Date: Tue, 29 Dec 2015 07:35:00 +0100
> Subject: [PATCH v2] lavf/qtpalette: Treat 1-bit video as palettized
> 
> I forgot some stuff. Patch description follows:
> 
> This patch for qtpalette.c and qtpalette.h adds 1-bit video to the
> "palettized video" category, since if the video sample description
> contains a palette, the two colors in the palette can be any color, not
> necessarily black & white.
> 

> Unfortunately, I've noticed that the qtrle (QuickTime Animation) decoder
> blindly assumes that 1-bit video is black & white. I don't have enough
> knowledge about the decoder to fix this, though.

the pix_fmt would need to be changed to AV_PIX_FMT_PAL8
probably qtrle_decode_1bpp would eed to be changed so that pixels
are stored one per byte instead of one per bit
see qtrle_decode_2n4bpp vs. qtrle_decode_1bpp


> 
> Below is a link to a sample 1-bit QuickTime Animation clip of a rotating
> earth that uses blueish colors, and they will be correctly rendered in
> QuickTime, but not in FFmpeg (which will use black & white).
> 
> https://drive.google.com/open?id=0B3_pEBoLs0faUlItWm9KaGJSTEE

patch applied

thanks

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

If a bugfix only changes things apparently unrelated to the bug with no
further explanation, that is a good sign that the bugfix is wrong.
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