[FFmpeg-devel] [PATCH 2/3] mpegvideo_parser: parse the output picture number
michael at niedermayer.cc
Wed Mar 7 02:55:29 EET 2018
On Sun, Feb 11, 2018 at 08:31:40PM +0200, Jan Ekström wrote:
> On Sun, Feb 11, 2018 at 7:52 PM, Michael Niedermayer
> <michael at niedermayer.cc> wrote:
> > should be ok unless its intended to also restore the MSB
> The value seemed to be 10bit and if the pointer is at the position
> right after the picture_start_code, then `buf << 2` would move the
> 8 bits left of data two bits leftwards, and `buf >> 6` would then
> move the topmost bits of the following byte to be the bottom-most
> Unless you mean that there's a forgotten `(uint16_t)` there as the end
> value has 10 bits of effective data, making the correct way of doing
> it something a la `(((uint16_t)buf) << 2) | (((uint16_t)buf) >>
it was more a question about our API
if output_picture_number is intended to be what it is called in english then
this patch is wrong as the number will frequently go back to 0 and
as more than 1024 pictures are output.
so taken as its english meaning, there would be code needed to increase(/decrease)
the MSB occasionally
OTOH if the field is intended to store a unspecified number of LSB only
i wonder what it could be used for
> > Theres no code using output_picture_number currently
> Seems like some API users utilize this value.
What do they do with it ?
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
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