[FFmpeg-devel] [PATCH 04/12] avcodec/avcodec: add AVCodecContext.alpha_mode

[Niklas Haas <ffmpeg@haasn.xyz>]

From: Niklas Haas <git@haasn.dev>

Following in the footsteps of the previous commit, this commit adds the
new fields to AVCodecContext so we can start properly setting it on codecs,
as well as limiting the list of supported options to detect a format mismatch
during encode.

This commit also sets up the necessary infrastructure to start using the
newly added field in all codecs.
---
 doc/APIchanges              | 4 ++++
 doc/codecs.texi             | 8 ++++++++
 libavcodec/avcodec.c        | 6 ++++++
 libavcodec/avcodec.h        | 8 ++++++++
 libavcodec/codec_internal.h | 5 +++++
 libavcodec/codec_par.c      | 3 +++
 libavcodec/codec_par.h      | 5 +++++
 libavcodec/decode.c         | 2 ++
 libavcodec/options_table.h  | 5 +++++
 libavcodec/version.h        | 4 ++--
 10 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/doc/APIchanges b/doc/APIchanges
index 601013b018..2e4736034d 100644
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -2,6 +2,10 @@ The last version increases of all libraries were on 2024-03-07
 
 API changes, most recent first:
 
+2025-02-xx - xxxxxxxxxx - lavc 61.34.100 - avcodec.h codec_par.h
+  Add AVCodecContext.alpha_mode, AVCodecParameters.alpha_mode, and
+  AV_CODEC_CONFIG_ALPHA_MODE.
+
 2025-02-xx - xxxxxxxxxx - lavu 59.58.100 - frame.h pixfmt.h
   Add AVAlphaMode, AVFrame.alpha_mode, av_alpha_mode_name() and
   av_alpha_mode_from_name().
diff --git a/doc/codecs.texi b/doc/codecs.texi
index f6bd50eb71..eec5d8e8c7 100644
--- a/doc/codecs.texi
+++ b/doc/codecs.texi
@@ -913,6 +913,14 @@ Possible values:
 
 @end table
 
+@item alpha_mode @var{integer} (@emph{decoding/encoding,video})
+Possible values:
+@table @samp
+@item premultiplied
+@item straight
+@end table
+
+
 @item log_level_offset @var{integer}
 Set the log level offset.
 
diff --git a/libavcodec/avcodec.c b/libavcodec/avcodec.c
index e7e2c09222..9fd6c47416 100644
--- a/libavcodec/avcodec.c
+++ b/libavcodec/avcodec.c
@@ -765,6 +765,8 @@ int ff_default_get_supported_config(const AVCodecContext *avctx,
                                     const void **out_configs,
                                     int *out_num_configs)
 {
+    const FFCodec *codec2 = ffcodec(codec);
+
     switch (config) {
 FF_DISABLE_DEPRECATION_WARNINGS
     case AV_CODEC_CONFIG_PIX_FORMAT:
@@ -792,6 +794,10 @@ FF_ENABLE_DEPRECATION_WARNINGS
         if (out_num_configs)
             *out_num_configs = 0;
         return 0;
+
+    case AV_CODEC_CONFIG_ALPHA_MODE:
+        WRAP_CONFIG(AVMEDIA_TYPE_VIDEO, codec2->alpha_modes, enum AVAlphaMode, AVALPHA_MODE_UNSPECIFIED);
+
     default:
         return AVERROR(EINVAL);
     }
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index 403f02d841..a6f1060165 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -2105,6 +2105,13 @@ typedef struct AVCodecContext {
      */
     AVFrameSideData  **decoded_side_data;
     int             nb_decoded_side_data;
+
+    /**
+     * Indicates how the alpha channel of the video is represented.
+     * - encoding: Set by user
+     * - decoding: Set by libavcodec
+     */
+    enum AVAlphaMode alpha_mode;
 } AVCodecContext;
 
 /**
@@ -2728,6 +2735,7 @@ enum AVCodecConfig {
     AV_CODEC_CONFIG_CHANNEL_LAYOUT, ///< AVChannelLayout, terminated by {0}
     AV_CODEC_CONFIG_COLOR_RANGE,    ///< AVColorRange, terminated by AVCOL_RANGE_UNSPECIFIED
     AV_CODEC_CONFIG_COLOR_SPACE,    ///< AVColorSpace, terminated by AVCOL_SPC_UNSPECIFIED
+    AV_CODEC_CONFIG_ALPHA_MODE,     ///< AVAlphaMode, terminated by AVALPHA_MODE_UNSPECIFIED
 };
 
 /**
diff --git a/libavcodec/codec_internal.h b/libavcodec/codec_internal.h
index 5b2db74590..29ce6d6c62 100644
--- a/libavcodec/codec_internal.h
+++ b/libavcodec/codec_internal.h
@@ -148,6 +148,11 @@ typedef struct FFCodec {
      */
     unsigned cb_type:3;
 
+    /**
+     * This field determines the alpha modes supported by an encoder.
+     */
+    const enum AVAlphaMode *alpha_modes;
+
     int priv_data_size;
     /**
      * @name Frame-level threading support functions
diff --git a/libavcodec/codec_par.c b/libavcodec/codec_par.c
index 790ea01d10..ddf349ceea 100644
--- a/libavcodec/codec_par.c
+++ b/libavcodec/codec_par.c
@@ -51,6 +51,7 @@ static void codec_parameters_reset(AVCodecParameters *par)
     par->framerate           = (AVRational){ 0, 1 };
     par->profile             = AV_PROFILE_UNKNOWN;
     par->level               = AV_LEVEL_UNKNOWN;
+    par->alpha_mode          = AVALPHA_MODE_UNSPECIFIED;
 }
 
 AVCodecParameters *avcodec_parameters_alloc(void)
@@ -165,6 +166,7 @@ int avcodec_parameters_from_context(AVCodecParameters *par,
         par->sample_aspect_ratio = codec->sample_aspect_ratio;
         par->video_delay         = codec->has_b_frames;
         par->framerate           = codec->framerate;
+        par->alpha_mode          = codec->alpha_mode;
         break;
     case AVMEDIA_TYPE_AUDIO:
         par->format           = codec->sample_fmt;
@@ -229,6 +231,7 @@ int avcodec_parameters_to_context(AVCodecContext *codec,
         codec->sample_aspect_ratio    = par->sample_aspect_ratio;
         codec->has_b_frames           = par->video_delay;
         codec->framerate              = par->framerate;
+        codec->alpha_mode             = par->alpha_mode;
         break;
     case AVMEDIA_TYPE_AUDIO:
         codec->sample_fmt       = par->format;
diff --git a/libavcodec/codec_par.h b/libavcodec/codec_par.h
index f4b9bb5c06..19b1d738dc 100644
--- a/libavcodec/codec_par.h
+++ b/libavcodec/codec_par.h
@@ -212,6 +212,11 @@ typedef struct AVCodecParameters {
      * Audio only. Number of samples to skip after a discontinuity.
      */
     int seek_preroll;
+
+    /**
+     * Video with alpha channel only. Alpha channel handling
+     */
+    enum AVAlphaMode alpha_mode;
 } AVCodecParameters;
 
 /**
diff --git a/libavcodec/decode.c b/libavcodec/decode.c
index cac7e620d2..68f1070c15 100644
--- a/libavcodec/decode.c
+++ b/libavcodec/decode.c
@@ -583,6 +583,8 @@ static int fill_frame_props(const AVCodecContext *avctx, AVFrame *frame)
         frame->color_range = avctx->color_range;
     if (frame->chroma_location == AVCHROMA_LOC_UNSPECIFIED)
         frame->chroma_location = avctx->chroma_sample_location;
+    if (frame->alpha_mode == AVALPHA_MODE_UNSPECIFIED)
+        frame->alpha_mode = avctx->alpha_mode;
 
     if (avctx->codec_type == AVMEDIA_TYPE_VIDEO) {
             if (!frame->sample_aspect_ratio.num)  frame->sample_aspect_ratio = avctx->sample_aspect_ratio;
diff --git a/libavcodec/options_table.h b/libavcodec/options_table.h
index 47da41b0ad..32f853bc54 100644
--- a/libavcodec/options_table.h
+++ b/libavcodec/options_table.h
@@ -358,6 +358,11 @@ static const AVOption avcodec_options[] = {
 {"bottomleft",  "Bottom-left", 0, AV_OPT_TYPE_CONST, {.i64 = AVCHROMA_LOC_BOTTOMLEFT },  INT_MIN, INT_MAX, V|E|D, .unit = "chroma_sample_location_type"},
 {"bottom",      "Bottom",      0, AV_OPT_TYPE_CONST, {.i64 = AVCHROMA_LOC_BOTTOM },      INT_MIN, INT_MAX, V|E|D, .unit = "chroma_sample_location_type"},
 {"unspecified", "Unspecified", 0, AV_OPT_TYPE_CONST, {.i64 = AVCHROMA_LOC_UNSPECIFIED }, INT_MIN, INT_MAX, V|E|D, .unit = "chroma_sample_location_type"},
+{"alpha_mode", "alpha mode", OFFSET(alpha_mode), AV_OPT_TYPE_INT, {.i64 = AVALPHA_MODE_UNSPECIFIED }, 0, INT_MAX, V|E|D, .unit = "alpha_mode_type"},
+{"unknown",       "Unspecified",   0, AV_OPT_TYPE_CONST, {.i64 = AVALPHA_MODE_UNSPECIFIED   }, 0, 0, V|E|D, .unit = "alpha_mode_type"},
+{"unspecified",   "Unspecified",   0, AV_OPT_TYPE_CONST, {.i64 = AVALPHA_MODE_UNSPECIFIED   }, 0, 0, V|E|D, .unit = "alpha_mode_type"},
+{"premultiplied", "Premultiplied", 0, AV_OPT_TYPE_CONST, {.i64 = AVALPHA_MODE_PREMULTIPLIED }, 0, 0, V|E|D, .unit = "alpha_mode_type"},
+{"straight",      "Straight",      0, AV_OPT_TYPE_CONST, {.i64 = AVALPHA_MODE_STRAIGHT      }, 0, 0, V|E|D, .unit = "alpha_mode_type"},
 {"log_level_offset", "set the log level offset", OFFSET(log_level_offset), AV_OPT_TYPE_INT, {.i64 = 0 }, INT_MIN, INT_MAX },
 {"slices", "set the number of slices, used in parallelized encoding", OFFSET(slices), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, INT_MAX, V|E},
 {"thread_type", "select multithreading type", OFFSET(thread_type), AV_OPT_TYPE_FLAGS, {.i64 = FF_THREAD_SLICE|FF_THREAD_FRAME }, 0, INT_MAX, V|A|E|D, .unit = "thread_type"},
diff --git a/libavcodec/version.h b/libavcodec/version.h
index 62e7eba3db..0ef6c991f3 100644
--- a/libavcodec/version.h
+++ b/libavcodec/version.h
@@ -29,8 +29,8 @@
 
 #include "version_major.h"
 
-#define LIBAVCODEC_VERSION_MINOR  33
-#define LIBAVCODEC_VERSION_MICRO 102
+#define LIBAVCODEC_VERSION_MINOR  34
+#define LIBAVCODEC_VERSION_MICRO 100
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
                                                LIBAVCODEC_VERSION_MINOR, \
-- 
2.47.0

_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".