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

Mats Peterson matsp888 at yahoo.com
Tue Dec 29 14:17:01 CET 2015


On 12/29/2015 11:56 AM, Michael Niedermayer wrote:
> 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
>
> [...]
>
>
>
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Thanks for suggestions and applied patch.

Mats

-- 
Mats Peterson
http://matsp888.no-ip.org/~mats/


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