[FFmpeg-devel] imagepipe filter (was [PATCH] avfilter: add dynoverlay filter.)

[Paul B Mahol]

On 9/28/16, Priebe, Jason <jpriebe at cbcnewmedia.com> wrote:
> On 9/23/16, Paul B Mahol <onemda at gmail.com> wrote:
>
>> On 9/27/16, Priebe, Jason <jpriebe at cbcnewmedia.com> wrote:
>> > On 9/23/16, Paul B Mahol <onemda at gmail.com> wrote:
>> >
>> > - it uses a slightly inelegant technique to read the images; it writes
>> >   the image data to a temp file so it can call ff_load_image().  I
>> > didn't
>> >   see a function that can load an image directly from an in-memory byte
>> > array.
>>
>> AVFrame stores all decoded data from image. Using temp files is
>> ridicculous.
>
> I do store the *decoded* image in an AVFrame.  I only use the temp file
> when I finish reading the *encoded* image from the named pipe -- I
> write to a temp file, hand that off to ff_load_image(), and once the
> image has been decoded, I destroy the temp file.
>
> Like I said, I don't see any way to decode an in-memory encoded
> image (PNG, JPG, etc.) with the existing function calls.  I only
> see ff_load_image(), which takes a filename.
>
> I think that trying to decode a PNG out of an in-memory buffer would
> require refactoring inside of files like libavformat/utils.c, which
> would require a deeper understanding of the internals than I have.
>
> If there's a better way to decode these still images without using
> an intermediate temp file, please point me to it, and I'll make the
> change.

Using avformat/avcodec calls to decode input from named pipe into AVFrame.