[FFmpeg-devel] [PATCH v4 00/22] avdevice (mostly dshow) enhancements

Diederick Niehorster dcnieho at gmail.com
Fri Mar 25 16:10:19 EET 2022

This patch series implements a series of features, mostly enhancing the
dshow avdevice, but also adding new functionality to avformat.
This whole patchset enabled users of the FFmpeg API to fully
query and control a dshow device, making FFmpeg a nice backend for any
program that needs access to, e.g., a webcam.

Different from v3, part of the patches has now been accepted, so only
remaining features are in this set. Importantly, as per discussion on
the list (
https://ffmpeg.org/pipermail/ffmpeg-devel/2021-June/281513.html, see
especially https://ffmpeg.org/pipermail/ffmpeg-devel/2021-June/281586.html),
to resolve the the unholy ABI-relationship between libavdevice and
libavformat and allow easier working on the part of the avdevice API
that lives in avformat, avdevice is now locked to a specific major and minor
version of avformat. This is documented in libavdevice/avdevice.h.

Regarding new functionality added to avformat:
Querying the capabilities of a dshow device is also possible on a
device that is already opened. I expect/guess however that it may not be
possible to achieve that for all of the avdevices, so in principle it is
important that this patchset adds the ability to create an allocated but
unopened AVFormatContext+AVInputFormat with the new function
avformat_alloc_input_context(). This is tested in the new
device_get_capabilities example.

Diederick Niehorster (22):
  avdevice/dshow: fix regression
  avdevice: lock to minor version of avformat
  avformat: add control_message function to AVInputFormat
  avdevice/dshow: implement control_message interface
  avdevice: add control message requesting to show config dialog
  avdevice/dshow: accept show config dialog control message
  avdevice/dshow: add config dialog command for crossbar and tv tuner
  avdevice/avdevice: Revert "Deprecate AVDevice Capabilities API"
  avdevice/avdevice: clean up avdevice_capabilities_create
  avdevice: capabilities API details no longer public
  avutil/opt: document AVOptionRange min_value > max_value
  avdevice: Add internal helpers for querying device capabilities
  avdevice: change device capabilities option type
  avdevice: improve capabilities' option API
  avdevice/dshow: move audio format helpers
  avdevice/dshow: when closing, set context fields back to zero
  avdevice/dshow: implement capabilities API
  avdevice/dshow: cosmetics
  avformat: add avformat_alloc_input_context()
  doc/examples: adding device_get_capabilities example
  Makefile/examples: cosmetics
  avdevice/dshow: capabilities query also works on opened device

 configure                              |   2 +
 doc/examples/.gitignore                |   1 +
 doc/examples/Makefile                  |  47 +-
 doc/examples/Makefile.example          |   1 +
 doc/examples/device_get_capabilities.c | 243 +++++++++
 doc/indevs.texi                        |  34 ++
 libavdevice/avdevice.c                 | 177 ++++++-
 libavdevice/avdevice.h                 | 111 ++---
 libavdevice/dshow.c                    | 662 ++++++++++++++++++++++---
 libavdevice/dshow_capture.h            |  14 +
 libavdevice/dshow_crossbar.c           |  91 ++--
 libavdevice/internal.h                 |  66 +++
 libavdevice/utils.c                    |  48 ++
 libavdevice/version.h                  |  15 +-
 libavdevice/version_major.h            |   2 +-
 libavformat/avformat.h                 |  59 ++-
 libavformat/demux.c                    |  74 ++-
 libavformat/utils.c                    |   5 +
 libavformat/version.h                  |  14 +-
 libavutil/avutil.h                     |   3 +
 libavutil/macros.h                     |   3 +
 libavutil/opt.c                        |   2 +-
 libavutil/opt.h                        |   5 +
 23 files changed, 1467 insertions(+), 212 deletions(-)
 create mode 100644 doc/examples/device_get_capabilities.c


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