[FFmpeg-devel] [PATCH] qsv.c: making qsv session routines common for libavcodec and libavfilter modules.

Ivan Uskov ivan.uskov at nablet.com
Fri Nov 13 08:57:59 CET 2015

Hello Hendrik,

Friday, November 13, 2015, 12:55:38 AM, you wrote:

HL> On Thu, Nov 12, 2015 at 10:15 PM, Ivan Uskov <ivan.uskov at nablet.com> wrote:
>> Hello All,
>> As  it  turned  out, a suggested recently libavfilter/vf_qsv_vpp.c may not use
>> ff_qsv_init_internal_session() from libavcodec/qsv.c.
>> The attached patch moves qsv.c and qsv_internal.h to libavutil subdir to make
>> corresponded routines common for codecs and filters.
>> First  argument  of  ff_qsv_init_internal_session()has been changed to accept
>> pointer to any context structure compatible with av_log().
>> Please review.

HL> Your patch does not work. Please test it with dynamic linking, and
HL> you'll immediately see it failing (hint: only av* symbols are
HL> exported)
Sorry, really released dynamic linking.
Ok, it can be fixed if it will necessary, thank.

HL> Secondly, I don't think exposing these internals as public API (which
HL> avutil generally is), would be a good idea at all.
HL> Heck the header is even called qsv_internal.h, stuff like this should
HL> never be used across library boundaries. It puts the API/ABI in stone,
HL> and hinders any future expansions or enhancements.
We can rename qsv_internal.h to qsv_common.h it is just question of <legacy> naming.
The  ff_qsv_init_internal_session() can be renamed to av_init_default_session()
etc  and  can  be used in user application. BTW, the current qsvdec.c example
would  to  use  such  API instead direct and non-portable VAAPI-related code
that currently works for linux platforms only.

HL> avutil is not a place we dump stuff that should be shared between
HL> avcodec and avfilter, or similar, avutil should generally be public
HL> useful API.
I believe 3 of 4 functions here can be published as useful API.
If   you   do  not  like  this  way,  could  you  please  advise some another
constructive  way to avoid a duplication of more then 300 code lines? Or copy
paste between codecs and filters is really best solution for this case?

Best regards,
 Ivan                            mailto:ivan.uskov at nablet.com

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