This fixes segmentation faults due to out of bounds writes, when
color_start is interpreted as negative number.
This regression was introduced in commit 57631f.
Reviewed-by: Mats Peterson <matsp888@yahoo.com>
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
The QuickTime File Format Specification states the following:
"Depth: A 16-bit integer that indicates the pixel depth of the
compressed image. Values of 1, 2, 4, 8 ,16, 24, and 32 indicate the
depth of color images. The value 32 should be used only if the image
contains an alpha channel. Values of 34, 36, and 40 indicate 2-, 4-, and
8-bit grayscale, respectively, for grayscale images."
There is no mention of value 33, i.e. 1-bit video (0x01) with the
greyscale bit (0x20) set. I therefore suggest that we ignore the
greyscale bit when processing 1-bit video. Another reason to do this is
that the first 1-bit sample file below will be displayed properly with
blue colors in QuickTime in Windows or Mac *in spite of* the greyscale
bit being set.
Also, QuickTime in Windows or Mac ignores the greyscale bit if the
video sample description contains a palette, regardless of bit depth.
This is undocumented behaviour, but I think we should do the same, and
it seems pretty logical after all, since one wouldn't really bother
putting a customized palette into a grayscale file anyway. See the
second 8-bit sample file below, which has the greyscale bit set, and
which contains a palette in the video sample description. In Windows or
Mac, it will be displayed with the palette in the sample description, in
spite of the greyscale bit being set.
Sample file 1 (1-bit QuickTime Animation):
https://drive.google.com/open?id=0B3_pEBoLs0faTThSek1EeXQ0ZHM
Earth Spin 1-bit qtrle orig.mov
Sample file 2 (8-bit QuickTime Animation):
https://drive.google.com/open?id=0B3_pEBoLs0fad2s0V1YzUWo5aDA
quiz-palette+gs.mov
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit 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
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This consists mainly of moving the palette handling from
the mov_parse_stsd_video() function to a new ff_get_qtpalette() function
in the new file qtpalette.c, which will be shared by both matroskadec.c and
mov.c.
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
