On Mon, 2 Jan 2017 14:26:45 -0700
pkoshe...@gmail.com wrote:
> From: Pavel Koshevoy <pkoshe...@gmail.com>
>
> Evidently CUVID doesn't support decoding 422 or 444 chroma formats,
> and only a limited set of resolutions per codec are supported.
>
> Given that stream resolution and pixel format are typically known as a
> result of probing it is better to use this info during avcodec_open2
> call and fail early in case the video parameters are not supported,
> rather than failing later during avcodec_send_packet calls.
>
> This problem surfaced when trying to decode 5120x2700 h246 video on
> Geforce GT 730, or when decoding 422 mpeg2 stream on same GPU --
> avcodec_open2 succeeded but decoding failed.
> ---
> libavcodec/cuvid.c | 58
> +++++++++++++++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 53 insertions(+), 5 deletions(-)
>
> diff --git a/libavcodec/cuvid.c b/libavcodec/cuvid.c
> index 8fc713d..febdd71 100644
> --- a/libavcodec/cuvid.c
> +++ b/libavcodec/cuvid.c
> @@ -612,7 +612,11 @@ static av_cold int cuvid_decode_end(AVCodecContext
> *avctx)
> return 0;
> }
>
> -static int cuvid_test_dummy_decoder(AVCodecContext *avctx, CUVIDPARSERPARAMS
> *cuparseinfo)
> +static int cuvid_test_dummy_decoder(AVCodecContext *avctx,
> + const CUVIDPARSERPARAMS *cuparseinfo,
> + cudaVideoChromaFormat
> probed_chroma_format,
> + int probed_width,
> + int probed_height)
> {
> CuvidContext *ctx = avctx->priv_data;
> CUVIDDECODECREATEINFO cuinfo;
> @@ -622,11 +626,11 @@ static int cuvid_test_dummy_decoder(AVCodecContext
> *avctx, CUVIDPARSERPARAMS *cu
> memset(&cuinfo, 0, sizeof(cuinfo));
>
> cuinfo.CodecType = cuparseinfo->CodecType;
> - cuinfo.ChromaFormat = cudaVideoChromaFormat_420;
> + cuinfo.ChromaFormat = probed_chroma_format;
> cuinfo.OutputFormat = cudaVideoSurfaceFormat_NV12;
>
> - cuinfo.ulWidth = 1280;
> - cuinfo.ulHeight = 720;
> + cuinfo.ulWidth = probed_width;
> + cuinfo.ulHeight = probed_height;
> cuinfo.ulTargetWidth = cuinfo.ulWidth;
> cuinfo.ulTargetHeight = cuinfo.ulHeight;
>
> @@ -653,6 +657,36 @@ static int cuvid_test_dummy_decoder(AVCodecContext
> *avctx, CUVIDPARSERPARAMS *cu
> return 0;
> }
>
> +static int convert_to_cuda_video_chroma_format(enum AVPixelFormat pix_fmt,
> + cudaVideoChromaFormat *out)
> +{
> + const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
> + if (!(out && desc &&
> + (desc->nb_components == 1 || desc->nb_components == 3) &&
> + (desc->log2_chroma_w < 2 && desc->log2_chroma_h < 2)))
> + {
> + return AVERROR(EINVAL);
> + }
> +
> + if (desc->nb_components == 1)
> + {
> + *out = cudaVideoChromaFormat_Monochrome;
> + }
> + else if (desc->flags == AV_PIX_FMT_FLAG_PLANAR)
> + {
> + *out = ((desc->log2_chroma_w == 0) ? cudaVideoChromaFormat_444 :
> + (desc->log2_chroma_h == 0) ? cudaVideoChromaFormat_422 :
> + cudaVideoChromaFormat_420);
> + }
> + else
> + {
> + return AVERROR(EINVAL);
> + }
> +
> + // unfortunately, 420 is the only one that works:
> + return (*out == cudaVideoChromaFormat_420) ? 0 : AVERROR_EXTERNAL;
> +}
> +
> static av_cold int cuvid_decode_init(AVCodecContext *avctx)
> {
> CuvidContext *ctx = avctx->priv_data;
> @@ -663,12 +697,23 @@ static av_cold int cuvid_decode_init(AVCodecContext
> *avctx)
> CUcontext cuda_ctx = NULL;
> CUcontext dummy;
> const AVBitStreamFilter *bsf;
> + cudaVideoChromaFormat probed_chroma_format;
> + int probed_width;
> + int probed_height;
> int ret = 0;
>
> enum AVPixelFormat pix_fmts[3] = { AV_PIX_FMT_CUDA,
> AV_PIX_FMT_NV12,
> AV_PIX_FMT_NONE };
>
> + ret = convert_to_cuda_video_chroma_format(avctx->pix_fmt,
> &probed_chroma_format);
> + if (ret < 0) {
> + // pixel format is not supported:
> + return ret;
> + }
> + probed_width = avctx->coded_width ? avctx->coded_width : 1280;
> + probed_height = avctx->coded_height ? avctx->coded_height : 720;
IMO relying on these fields is a bit of a problem, since they don't
even need to be set (the h264 bitstream can contain them).
It's especially bad for pix_fmt, since my application for example
doesn't set this field at all in many cases.
> +
> // Accelerated transcoding scenarios with 'ffmpeg' require that the
> // pix_fmt be set to AV_PIX_FMT_CUDA early. The sw_pix_fmt, and the
> // pix_fmt for non-accelerated transcoding, do not need to be correct
> @@ -824,7 +869,10 @@ static av_cold int cuvid_decode_init(AVCodecContext
> *avctx)
> if (ret < 0)
> goto error;
>
> - ret = cuvid_test_dummy_decoder(avctx, &ctx->cuparseinfo);
> + ret = cuvid_test_dummy_decoder(avctx, &ctx->cuparseinfo,
> + probed_chroma_format,
> + probed_width,
> + probed_height);
> if (ret < 0)
> goto error;
>
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