When encoding VP9 with a YUV pixel format (e.g. yuv420p) and
AVCOL_SPC_RGB colorspace metadata, libvpxenc unconditionally set
VPX_CS_SRGB. This produced a spec-violating bitstream: Profile 0
(4:2:0) with sRGB colorspace, which is only valid for Profile 1/3
(4:4:4). The resulting file is undecodable.
Fix this by setting ctx->vpx_cs to VPX_CS_SRGB in set_pix_fmt()
for 4:4:4 YUV formats when AVCOL_SPC_RGB is set, matching the
existing GBRP path. This covers the legitimate case of RGB data in
YUV444 containers (e.g. H.264 High 4:4:4 with identity matrix).
With this change, any AVCOL_SPC_RGB that reaches the switch in
set_colorspace() is guaranteed to be a subsampled format where
sRGB is invalid. Return an error so the user can fix their
pipeline rather than silently producing incorrect output.
To reproduce:
ffmpeg -f lavfi -i testsrc=s=64x64:d=1:r=1 \
-c:v libvpx-vp9 -pix_fmt yuv420p -colorspace rgb bad.webm
ffprobe bad.webm
# -> "vp9 (Profile 0), none(pc, gbr/...), 64x64"
ffmpeg -i bad.webm -f null -
# -> 0 frames decoded, error
Signed-off-by: Guangyu Sun <[email protected]>
---
v2:
- Only fall back to BT.709 if the pixel format is not 4:4:4,
addressing feedback regarding Profile 1/3 support.
v3:
- Hard error via AVERROR(EINVAL) - set_colorspace() now returns
int, and the call site in vpx_init() propagates the error
libavcodec/libvpxenc.c | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/libavcodec/libvpxenc.c b/libavcodec/libvpxenc.c
index 88c058c403..c181927a1d 100644
--- a/libavcodec/libvpxenc.c
+++ b/libavcodec/libvpxenc.c
@@ -838,6 +838,8 @@ static int set_pix_fmt(AVCodecContext *avctx,
vpx_codec_caps_t codec_caps,
ctx->vpx_cs = VPX_CS_SRGB;
case AV_PIX_FMT_YUV444P:
case AV_PIX_FMT_YUVA444P:
+ if (avctx->colorspace == AVCOL_SPC_RGB)
+ ctx->vpx_cs = VPX_CS_SRGB;
enccfg->g_profile = 1;
*img_fmt = VPX_IMG_FMT_I444;
return 0;
@@ -879,6 +881,8 @@ static int set_pix_fmt(AVCodecContext *avctx,
vpx_codec_caps_t codec_caps,
case AV_PIX_FMT_YUVA444P10:
case AV_PIX_FMT_YUV444P12:
case AV_PIX_FMT_YUVA444P12:
+ if (avctx->colorspace == AVCOL_SPC_RGB)
+ ctx->vpx_cs = VPX_CS_SRGB;
if (codec_caps & VPX_CODEC_CAP_HIGHBITDEPTH) {
enccfg->g_profile = 3;
*img_fmt = VPX_IMG_FMT_I44416;
@@ -893,7 +897,7 @@ static int set_pix_fmt(AVCodecContext *avctx,
vpx_codec_caps_t codec_caps,
return AVERROR_INVALIDDATA;
}
-static void set_colorspace(AVCodecContext *avctx)
+static int set_colorspace(AVCodecContext *avctx)
{
enum vpx_color_space vpx_cs;
VPxContext *ctx = avctx->priv_data;
@@ -902,7 +906,11 @@ static void set_colorspace(AVCodecContext *avctx)
vpx_cs = ctx->vpx_cs;
} else {
switch (avctx->colorspace) {
- case AVCOL_SPC_RGB: vpx_cs = VPX_CS_SRGB; break;
+ case AVCOL_SPC_RGB:
+ av_log(avctx, AV_LOG_ERROR,
+ "RGB colorspace is not compatible with pixel format %s.\n",
+ av_get_pix_fmt_name(avctx->pix_fmt));
+ return AVERROR(EINVAL);
case AVCOL_SPC_BT709: vpx_cs = VPX_CS_BT_709; break;
case AVCOL_SPC_UNSPECIFIED: vpx_cs = VPX_CS_UNKNOWN; break;
case AVCOL_SPC_RESERVED: vpx_cs = VPX_CS_RESERVED; break;
@@ -913,10 +921,11 @@ static void set_colorspace(AVCodecContext *avctx)
default:
av_log(avctx, AV_LOG_WARNING, "Unsupported colorspace (%d)\n",
avctx->colorspace);
- return;
+ return 0;
}
}
codecctl_int(avctx, VP9E_SET_COLOR_SPACE, vpx_cs);
+ return 0;
}
#if VPX_ENCODER_ABI_VERSION >= 11
@@ -1277,7 +1286,9 @@ static av_cold int vpx_init(AVCodecContext *avctx,
codecctl_int(avctx, VP9E_SET_FRAME_PARALLEL_DECODING,
ctx->frame_parallel);
if (ctx->aq_mode >= 0)
codecctl_int(avctx, VP9E_SET_AQ_MODE, ctx->aq_mode);
- set_colorspace(avctx);
+ res = set_colorspace(avctx);
+ if (res < 0)
+ return res;
#if VPX_ENCODER_ABI_VERSION >= 11
set_color_range(avctx);
#endif
--
2.52.0
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