[FFmpeg-devel] [PATCH 5/7] avcodec/encode: enforce AVCodec capabilities at encode time

[Niklas Haas]

From: Niklas Haas <git at haasn.dev>

In general, the logic is always the same: if the codec supports only a
single format, enforce it if possible. Otherwise, throw an error when
an incompatible format is thrown.

To preserve backwards compatibility and make this check less pedantic
than it needs to be, always consider 'AVCOL_*_UNKNOWN/UNSPECIFIED' a
valid value. That way, we will only throw an error if the user
explicitly set a color value that we explicitly know is unsupported.
---
 libavcodec/encode.c | 102 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 102 insertions(+)

diff --git a/libavcodec/encode.c b/libavcodec/encode.c
index a436be2657..f22b17f33e 100644
--- a/libavcodec/encode.c
+++ b/libavcodec/encode.c
@@ -611,6 +611,108 @@ static int encode_preinit_video(AVCodecContext *avctx)
             avctx->color_range = AVCOL_RANGE_JPEG;
     }
 
+    if (c->csps) {
+        for (i = 0; c->csps[i] != AVCOL_SPC_UNSPECIFIED; i++)
+            if (avctx->colorspace == c->csps[i])
+                break;
+        if (c->csps[i] == AVCOL_SPC_UNSPECIFIED) {
+            av_log(avctx, AV_LOG_ERROR,
+                   "Specified colorspace %s is not supported by the %s encoder.\n",
+                   av_color_space_name(avctx->colorspace), c->name);
+            av_log(avctx, AV_LOG_ERROR, "Supported colorspaces:\n");
+            for (int p = 0; c->csps[p] != AVCOL_SPC_UNSPECIFIED; p++) {
+                av_log(avctx, AV_LOG_ERROR, "  %s\n",
+                       av_color_space_name(c->csps[p]));
+            }
+            return AVERROR(EINVAL);
+        }
+    }
+
+    if (c->color_ranges) {
+        for (i = 0; c->color_ranges[i] != AVCOL_RANGE_UNSPECIFIED; i++) {
+            if (avctx->color_range == c->color_ranges[i])
+                break;
+        }
+        if (c->color_ranges[i] == AVCOL_RANGE_UNSPECIFIED) {
+            if (i == 1 && !avctx->color_range) {
+                avctx->color_range = c->color_ranges[0];
+            } else if (avctx->color_range) {
+                av_log(avctx, AV_LOG_ERROR,
+                       "Specified color range %s is not supported by the %s encoder.\n",
+                       av_color_range_name(avctx->color_range), c->name);
+                av_log(avctx, AV_LOG_ERROR, "Supported color ranges:\n");
+                for (int p = 0; c->color_ranges[p] != AVCOL_RANGE_UNSPECIFIED; p++) {
+                    av_log(avctx, AV_LOG_ERROR, "  %s\n",
+                           av_color_range_name(c->color_ranges[p]));
+                }
+                return AVERROR(EINVAL);
+            }
+        }
+    }
+
+    if (c->chroma_locs) {
+        for (i = 0; c->chroma_locs[i] != AVCHROMA_LOC_UNSPECIFIED; i++)
+            if (avctx->chroma_sample_location == c->chroma_locs[i])
+                break;
+        if (c->chroma_locs[i] == AVCHROMA_LOC_UNSPECIFIED) {
+            if (i == 1 && !avctx->chroma_sample_location) {
+                avctx->chroma_sample_location = c->chroma_locs[0];
+            } else if (avctx->chroma_sample_location) {
+                av_log(avctx, AV_LOG_ERROR,
+                       "Specified chroma sample location %s is not supported by the %s encoder.\n",
+                       av_chroma_location_name(avctx->chroma_sample_location), c->name);
+                av_log(avctx, AV_LOG_ERROR, "Supported chroma sample locations:\n");
+                for (int p = 0; c->chroma_locs[p] != AVCHROMA_LOC_UNSPECIFIED; p++) {
+                    av_log(avctx, AV_LOG_ERROR, "  %s\n",
+                           av_chroma_location_name(c->chroma_locs[p]));
+                }
+                return AVERROR(EINVAL);
+            }
+        }
+    }
+
+    if (c->primaries) {
+        for (i = 0; c->primaries[i] != AVCOL_PRI_UNSPECIFIED; i++)
+            if (avctx->color_primaries == c->primaries[i])
+                break;
+        if (c->primaries[i] == AVCOL_PRI_UNSPECIFIED) {
+            if (i == 1 && !avctx->color_primaries) {
+                avctx->color_primaries = c->primaries[0];
+            } else if (avctx->color_primaries) {
+                av_log(avctx, AV_LOG_ERROR,
+                       "Specified color primaries %s is not supported by the %s encoder.\n",
+                       av_color_primaries_name(avctx->color_primaries), c->name);
+                av_log(avctx, AV_LOG_ERROR, "Supported color primaries:\n");
+                for (int p = 0; c->primaries[p] != AVCOL_PRI_UNSPECIFIED; p++) {
+                    av_log(avctx, AV_LOG_ERROR, "  %s\n",
+                           av_color_primaries_name(c->primaries[p]));
+                }
+                return AVERROR(EINVAL);
+            }
+        }
+    }
+
+    if (c->trcs) {
+        for (i = 0; c->trcs[i] != AVCOL_TRC_UNSPECIFIED; i++)
+            if (avctx->color_trc == c->trcs[i])
+                break;
+        if (c->trcs[i] == AVCOL_TRC_UNSPECIFIED) {
+            if (i == 1 && !avctx->color_trc) {
+                avctx->color_trc = c->trcs[0];
+            } else if (avctx->color_trc) {
+                av_log(avctx, AV_LOG_ERROR,
+                       "Specified color transfer characteristics %s is not supported by the %s encoder.\n",
+                       av_color_transfer_name(avctx->color_trc), c->name);
+                av_log(avctx, AV_LOG_ERROR, "Supported color transfer characteristics:\n");
+                for (int p = 0; c->trcs[p] != AVCOL_TRC_UNSPECIFIED; p++) {
+                    av_log(avctx, AV_LOG_ERROR, "  %s\n",
+                           av_color_transfer_name(c->trcs[p]));
+                }
+                return AVERROR(EINVAL);
+            }
+        }
+    }
+
     if (    avctx->bits_per_raw_sample < 0
         || (avctx->bits_per_raw_sample > 8 && pixdesc->comp[0].depth <= 8)) {
         av_log(avctx, AV_LOG_WARNING, "Specified bit depth %d not possible with the specified pixel formats depth %d\n",
-- 
2.42.0