[PATCH 3/3] winegstreamer: Support dynamic H264 decoder output format change.

[Zebediah Figura]

On 4/5/22 07:26, Rémi Bernon wrote:
> @@ -70,11 +70,18 @@ static HRESULT try_create_wg_transform(struct h264_decoder *decoder)
>       if (input_format.major_type == WG_MAJOR_TYPE_UNKNOWN)
>           return MF_E_INVALIDMEDIATYPE;
>   
> -    mf_media_type_to_wg_format(decoder->output_type, &output_format);
> -    if (output_format.major_type == WG_MAJOR_TYPE_UNKNOWN)
> +    mf_media_type_to_wg_format(decoder->output_type, &decoder->output_format);
> +    if (decoder->output_format.major_type == WG_MAJOR_TYPE_UNKNOWN)
>           return MF_E_INVALIDMEDIATYPE;
>   
> -    if (!(decoder->wg_transform = wg_transform_create(&input_format, &output_format)))
> +    /* Don't force any output frame size, H264 streams already have the
> +     * metadata for it and will generate a MF_E_TRANSFORM_STREAM_CHANGE
> +     * result later.
> +     */
> +    decoder->output_format.u.video.width = 0;
> +    decoder->output_format.u.video.height = 0;

This seems like it's orthogonal to dynamic format change.

It also leads me to wonder: do we need the output_type field at all if 
we're going to have decoder->output_format?

> +
> +    if (!(decoder->wg_transform = wg_transform_create(&input_format, &decoder->output_format)))
>           return E_FAIL;
>   
>       return S_OK;
> @@ -369,7 +376,7 @@ static HRESULT WINAPI transform_GetOutputAvailableType(IMFTransform *iface, DWOR
>       if (FAILED(hr = IMFMediaType_SetGUID(media_type, &MF_MT_SUBTYPE, output_type)))
>           goto done;
>   
> -    hr = fill_output_media_type(media_type, NULL);
> +    hr = fill_output_media_type(media_type, decoder->output_type);
>   
>   done:
>       if (SUCCEEDED(hr))

This also seems like it's orthogonal to dynamic format change. (Is it 
possible to write tests for this?)

> @@ -418,6 +425,7 @@ static HRESULT WINAPI transform_SetOutputType(IMFTransform *iface, DWORD id, IMF
>   {
>       struct h264_decoder *decoder = impl_from_IMFTransform(iface);
>       GUID major, subtype;
> +    BOOL identical;
>       HRESULT hr;
>       ULONG i;
>   
> @@ -440,7 +448,14 @@ static HRESULT WINAPI transform_SetOutputType(IMFTransform *iface, DWORD id, IMF
>           return MF_E_INVALIDMEDIATYPE;
>   
>       if (decoder->output_type)
> +    {
> +        fill_output_media_type(decoder->output_type, NULL);
> +        if (SUCCEEDED(hr = IMFMediaType_Compare(decoder->output_type, (IMFAttributes *)type,
> +                MF_ATTRIBUTES_MATCH_THEIR_ITEMS, &identical)) && identical)
> +            return S_OK;

So we require the user to specify meaningless 29.97 frame rate (and so 
on), and reject different real values?

This is awfully surprising behaviour; do we have tests for it?

>           IMFMediaType_Release(decoder->output_type);
> +    }
> +
>       IMFMediaType_AddRef((decoder->output_type = type));
>   
>       if (FAILED(hr = try_create_wg_transform(decoder)))
> @@ -490,7 +505,23 @@ static HRESULT WINAPI transform_ProcessEvent(IMFTransform *iface, DWORD id, IMFM
>   
>   static HRESULT WINAPI transform_ProcessMessage(IMFTransform *iface, MFT_MESSAGE_TYPE message, ULONG_PTR param)
>   {
> +    struct h264_decoder *decoder = impl_from_IMFTransform(iface);
> +
>       FIXME("iface %p, message %#x, param %Ix stub!\n", iface, message, param);
> +
> +    switch (message)
> +    {
> +    case MFT_MESSAGE_NOTIFY_BEGIN_STREAMING:
> +        /* Call of Duty Black Ops 3 expects to receive an MF_E_TRANSFORM_STREAM_CHANGE result again
> +         * after it has called ProcessMessage with BEGIN_STREAMING. We could destroy and re-create
> +         * the wg_transform instead but resetting the output format should be enough.
> +         */
> +        memset(&decoder->output_format, 0, sizeof(decoder->output_format));
> +        break;
> +    default:
> +        break;
> +    }
> +
>       return S_OK;
>   }
>   
> @@ -524,6 +555,8 @@ static HRESULT WINAPI transform_ProcessOutput(IMFTransform *iface, DWORD flags,
>       struct h264_decoder *decoder = impl_from_IMFTransform(iface);
>       MFT_OUTPUT_STREAM_INFO info;
>       struct wg_sample *wg_sample;
> +    IMFMediaType *media_type;
> +    UINT64 frame_rate;
>       HRESULT hr;
>   
>       TRACE("iface %p, flags %#lx, count %lu, samples %p, status %p.\n", iface, flags, count, samples, status);
> @@ -537,6 +570,9 @@ static HRESULT WINAPI transform_ProcessOutput(IMFTransform *iface, DWORD flags,
>       if (!decoder->wg_transform)
>           return MF_E_TRANSFORM_TYPE_NOT_SET;
>   
> +    if (FAILED(IMFMediaType_GetUINT64(decoder->output_type, &MF_MT_FRAME_RATE, &frame_rate)))
> +        frame_rate = (UINT64)30000 << 32 | 1001;
> +
>       *status = 0;
>       samples[0].dwStatus = 0;
>       if (!samples[0].pSample) return E_INVALIDARG;
> @@ -544,11 +580,24 @@ static HRESULT WINAPI transform_ProcessOutput(IMFTransform *iface, DWORD flags,
>       if (FAILED(hr = mf_create_wg_sample(samples[0].pSample, &wg_sample)))
>           return hr;
>   
> +    wg_sample->format = &decoder->output_format;
>       if (wg_sample->max_size < info.cbSize)
>           hr = MF_E_BUFFERTOOSMALL;
>       else
>           hr = wg_transform_read_data(decoder->wg_transform, wg_sample);
>   
> +    if (hr == MF_E_TRANSFORM_STREAM_CHANGE)
> +    {
> +        media_type = mf_media_type_from_wg_format(&decoder->output_format);
> +        IMFMediaType_SetUINT64(media_type, &MF_MT_FRAME_RATE, frame_rate);

So if the user never requests a specific frame rate, then we always 
force it to 29.97? And we ignore dynamic frame rate changes?

This is also surprising; do we have tests for these?

> +
> +        IMFMediaType_Release(decoder->output_type);
> +        decoder->output_type = media_type;
> +
> +        samples[0].dwStatus |= MFT_OUTPUT_DATA_BUFFER_FORMAT_CHANGE;
> +        *status |= MFT_OUTPUT_DATA_BUFFER_FORMAT_CHANGE;
> +    }
> +
>       mf_destroy_wg_sample(wg_sample);
>       return hr;
>   }