[FFmpeg-devel] [PATCH v3] lavfi: add new iteration API

[Josh Allmann]

Hi,

On Sat, 24 Mar 2018 at 14:40, Josh de Kock <josh at itanimul.li> wrote:
>
> Signed-off-by: Josh de Kock <josh at itanimul.li>
> ---
>  configure                |  29 +-
>  doc/APIchanges           |   4 +
>  doc/writing_filters.txt  |   6 +-
>  libavfilter/allfilters.c | 823 +++++++++++++++++++++++++----------------------
>  libavfilter/avfilter.c   |  50 +--
>  libavfilter/avfilter.h   |  29 +-
>  libavfilter/version.h    |   3 +
>  7 files changed, 489 insertions(+), 455 deletions(-)
>

This is a couple years too late, but wanted to drop a note that this
particular API change was breaking : it made avfilter_register a
no-op. The consequence is that it's much more difficult to maintain
filters out-of-tree; preserving the old behavior without changes to
user code requires a special build of ffmpeg that has the filter
configured/compiled in. The recommended workaround of using
avfilter_graph_alloc_filter requires more effort to wire the filter in
explicitly. It also doesn't allow for conveniences such as using
avfilter_graph_parse, since there doesn't seem to be a way to make
filters accessible via avfilter_get_by_name outside of ffmpeg compile
time.

If there is another workaround that I'm missing, please let me know,
or if there's some deeper rationale for the decision to disable this
feature.

Josh