[FFmpeg-devel] [PATCH] hwcontext_vdpau: implement av_hwdevice_get_hwframe_constraints()

[Mark Thompson]

On 15/01/18 11:22, wm4 wrote:
> On Mon, 15 Jan 2018 11:17:39 +0000
> Mark Thompson <sw at jkqxz.net> wrote:
> 
>> On 13/01/18 06:06, wm4 wrote:
>>> In addition, this does not allow creating frames contexts with sw_format
>>> for which no known transfer formats exist. In theory, we should check
>>> whether the chroma format (i.e. the sw_format) is supported at all by
>>> the vdpau driver, but checking for transfer formats has the same effect.
>>>
>>> Note that the pre-existing code adds 1 to priv->nb_pix_fmts[i] for
>>> unknown reason, and some checks need to account for that to check for
>>> empty lists. They are not off-by-one errors.
>>> ---
>>>  libavutil/hwcontext_vdpau.c | 55 ++++++++++++++++++++++++++++++++-------------
>>>  1 file changed, 39 insertions(+), 16 deletions(-)
>>>
>>> diff --git a/libavutil/hwcontext_vdpau.c b/libavutil/hwcontext_vdpau.c
>>> index 9b8f839647..c11c3cfdab 100644
>>> --- a/libavutil/hwcontext_vdpau.c
>>> +++ b/libavutil/hwcontext_vdpau.c
>>> @@ -79,11 +79,12 @@ static const VDPAUPixFmtMap pix_fmts_444[] = {
>>>  
>>>  static const struct {
>>>      VdpChromaType chroma_type;
>>> +    enum AVPixelFormat frames_sw_format;
>>>      const VDPAUPixFmtMap *map;
>>>  } vdpau_pix_fmts[] = {
>>> -    { VDP_CHROMA_TYPE_420, pix_fmts_420 },
>>> -    { VDP_CHROMA_TYPE_422, pix_fmts_422 },
>>> -    { VDP_CHROMA_TYPE_444, pix_fmts_444 },
>>> +    { VDP_CHROMA_TYPE_420, AV_PIX_FMT_YUV420P, pix_fmts_420 },
>>> +    { VDP_CHROMA_TYPE_422, AV_PIX_FMT_YUV422P, pix_fmts_422 },
>>> +    { VDP_CHROMA_TYPE_444, AV_PIX_FMT_YUV444P, pix_fmts_444 },
>>>  };
>>>  
>>>  static int count_pixfmts(const VDPAUPixFmtMap *map)
>>> @@ -170,6 +171,35 @@ static void vdpau_device_uninit(AVHWDeviceContext *ctx)
>>>          av_freep(&priv->pix_fmts[i]);
>>>  }
>>>  
>>> +static int vdpau_frames_get_constraints(AVHWDeviceContext *ctx,
>>> +                                        const void *hwconfig,
>>> +                                        AVHWFramesConstraints *constraints)
>>> +{
>>> +    VDPAUDeviceContext   *priv  = ctx->internal->priv;
>>> +    int nb_sw_formats = 0;
>>> +    int i;
>>> +
>>> +    constraints->valid_sw_formats = av_malloc_array(FF_ARRAY_ELEMS(vdpau_pix_fmts) + 1,
>>> +                                                    sizeof(*constraints->valid_sw_formats));
>>> +    if (!constraints->valid_sw_formats)
>>> +        return AVERROR(ENOMEM);
>>> +
>>> +    for (i = 0; i < FF_ARRAY_ELEMS(vdpau_pix_fmts); i++) {
>>> +        if (priv->nb_pix_fmts[i] > 1)
>>> +            constraints->valid_sw_formats[nb_sw_formats++] = vdpau_pix_fmts[i].frames_sw_format;
>>> +    }
>>> +    constraints->valid_sw_formats[nb_sw_formats] = AV_PIX_FMT_NONE;
>>> +
>>> +    constraints->valid_hw_formats = av_malloc_array(2, sizeof(*constraints->valid_hw_formats));
>>> +    if (!constraints->valid_hw_formats)
>>> +        return AVERROR(ENOMEM);
>>> +
>>> +    constraints->valid_hw_formats[0] = AV_PIX_FMT_VDPAU;
>>> +    constraints->valid_hw_formats[1] = AV_PIX_FMT_NONE;
>>> +
>>> +    return 0;
>>> +}
>>> +
>>>  static void vdpau_buffer_free(void *opaque, uint8_t *data)
>>>  {
>>>      AVHWFramesContext          *ctx = opaque;
>>> @@ -214,26 +244,18 @@ static int vdpau_frames_init(AVHWFramesContext *ctx)
>>>  
>>>      int i;
>>>  
>>> -    switch (ctx->sw_format) {
>>> -    case AV_PIX_FMT_YUV420P: priv->chroma_type = VDP_CHROMA_TYPE_420; break;
>>> -    case AV_PIX_FMT_YUV422P: priv->chroma_type = VDP_CHROMA_TYPE_422; break;
>>> -    case AV_PIX_FMT_YUV444P: priv->chroma_type = VDP_CHROMA_TYPE_444; break;
>>> -    default:
>>> -        av_log(ctx, AV_LOG_ERROR, "Unsupported data layout: %s\n",
>>> -               av_get_pix_fmt_name(ctx->sw_format));
>>> -        return AVERROR(ENOSYS);
>>> -    }
>>> -
>>>      for (i = 0; i < FF_ARRAY_ELEMS(vdpau_pix_fmts); i++) {
>>> -        if (vdpau_pix_fmts[i].chroma_type == priv->chroma_type) {
>>> +        if (vdpau_pix_fmts[i].frames_sw_format == ctx->sw_format) {
>>> +            priv->chroma_type = vdpau_pix_fmts[i].chroma_type;
>>>              priv->chroma_idx  = i;
>>>              priv->pix_fmts    = device_priv->pix_fmts[i];
>>>              priv->nb_pix_fmts = device_priv->nb_pix_fmts[i];
>>>              break;
>>>          }
>>>      }
>>> -    if (!priv->pix_fmts) {
>>> -        av_log(ctx, AV_LOG_ERROR, "Unsupported chroma type: %d\n", priv->chroma_type);
>>> +    if (priv->nb_pix_fmts < 2) {  
>>
>> I think keeping the (equivalent) older check of !priv->pix_fmts would look slightly clearer?
> 
> I don't think that would be the same. Checking priv->pix_fmts tells you
> that there was a matching chroma type, but checking nb_pix_fmts < 2
> tells you in addition whether there is any working sw_format. That in
> turn is needed to tell whether the vdpau implementation supports the
> chroma format at all.

Right, priv->pix_fmts could be a valid list containing nothing.  Then yes, use your way.

Thanks,

- Mark