[vlc-devel] [PATCH 3/3] cvpx: add smarter CVPX->SW chroma+resize converter
Thomas Guillem
thomas at gllm.fr
Thu Jun 18 13:33:45 CEST 2020
On Thu, Jun 18, 2020, at 10:50, Alexandre Janniaux wrote:
> CVPX -> CVPX chroma conversion filter is using HW-accelerated chroma
> conversion (VTPixelTransfer) on MacOSX, which is also able to resize
> pictures efficiently.
>
> However, when generating pictures with VLC_CODEC_CVPX_BGRA as i_chroma,
> the core will add the following conversion chain:
>
> CVPB (WxH) -> BGRA (WxH) -> I422 (WxH) -> I420 (W'xH')
>
> Instead, by using this new filter with a higher priority, we can detect
> that resize must be performed between CVPX buffers and directly convert
> to the most suitable CVPX chroma type, leading to the following
> conversion chain:
>
> CVPB (WxH) -> CVPI (W'xH') -> I420 (W'xH')
So, we already have a cvpx filter that can convert and resize? I didn't know it was capable to do that in one shot.
>
> Which has the benefit to never use swscale while avoiding an additional
> conversion, and transform the last conversion into only a memory
> mapping.
> ---
> modules/video_chroma/cvpx.c | 175 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 175 insertions(+)
>
> diff --git a/modules/video_chroma/cvpx.c b/modules/video_chroma/cvpx.c
> index 1614aeb7ee..6b4742cfdb 100644
> --- a/modules/video_chroma/cvpx.c
> +++ b/modules/video_chroma/cvpx.c
> @@ -43,6 +43,9 @@ static void Close(vlc_object_t *);
> #if !TARGET_OS_IPHONE
> static int Open_CVPX_to_CVPX(vlc_object_t *);
> static void Close_CVPX_to_CVPX(vlc_object_t *);
> +
> +static int Open_chain_CVPX(vlc_object_t *);
> +static void Close_chain_CVPX(vlc_object_t *);
> #endif
>
> typedef struct
> @@ -69,6 +72,11 @@ vlc_module_begin ()
> add_submodule()
> set_description("Conversions between CoreVideo buffers")
> set_callbacks(Open_CVPX_to_CVPX, Close_CVPX_to_CVPX)
> +
> + add_submodule()
> + set_description("Fast CoreVideo resize+conversion")
> + set_callbacks(Open_chain_CVPX, Close_chain_CVPX)
> + set_capability("video converter", 11)
> #endif
> vlc_module_end ()
>
> @@ -475,4 +483,171 @@ Close_CVPX_to_CVPX(vlc_object_t *obj)
> free(filter->p_sys);
> }
>
> +static picture_t*
> +chain_CVPX_Filter(filter_t *filter, picture_t *pic)
> +{
> + filter_chain_t *chain = filter->p_sys;
> + return filter_chain_VideoFilter(chain, pic);
> +}
> +
> +static void
> +chain_CVPX_Flush(filter_t *filter)
> +{
> + filter_chain_t *chain = filter->p_sys;
> + filter_chain_VideoFlush(chain);
> +}
> +
> +static vlc_fourcc_t
> +GetIntermediateChroma(input_chroma, output_chroma)
> +{
> + vlc_fourcc_t chromas[2] = { input_chroma, output_chroma };
> +
> + for(size_t i=0; i<ARRAY_SIZE(chromas); ++i)
> + {
> + switch (chromas[i])
> + {
> + case VLC_CODEC_I420: return VLC_CODEC_CVPX_I420;
> + case VLC_CODEC_BGRA: return VLC_CODEC_CVPX_BGRA;
> + case VLC_CODEC_NV12: return VLC_CODEC_CVPX_NV12;
> + default: break;
> + }
> + }
> +
> + vlc_assert_unreachable();
> +}
> +
> +static int
> +displayChain(filter_t *filter, void *opaque)
Nit: diplay*() in a video filter is generally used to do the actual rendering. I suggest debugChain or printChain.
> +{
> + VLC_UNUSED(opaque);
> + msg_Dbg(filter, " - conversion %4.4s (%dx%d) -> %4.4s (%dx%d)",
> + (const char*)&filter->fmt_in.video.i_chroma,
> + filter->fmt_in.video.i_visible_width,
> + filter->fmt_in.video.i_visible_height,
> + (const char*)&filter->fmt_out.video.i_chroma,
> + filter->fmt_out.video.i_visible_width,
> + filter->fmt_out.video.i_visible_height);
> + return VLC_SUCCESS;
> +}
> +
> +static const vlc_fourcc_t supported_sw_chromas[] = {
> + VLC_CODEC_I420, VLC_CODEC_BGRA, VLC_CODEC_NV12
> +};
> +
> +static int
> +Open_chain_CVPX(vlc_object_t *obj)
> +{
> + filter_t *filter = (filter_t *)obj;
> +
> + bool is_input_valid = false;
> + bool is_output_valid = false;
> +
> + /* Check whether we're already in a CVPX chain or not, to avoid
> + * looping on the same conversion. */
> + vlc_value_t is_in_chain;
> + int ret = var_GetChecked(vlc_object_parent(filter),
> "cvpx-chroma-chain",
> + VLC_VAR_BOOL, &is_in_chain);
> +
> + if (ret == VLC_SUCCESS && is_in_chain.b_bool )
> + return VLC_EGENERIC;
> +
> + vlc_fourcc_t input_chroma = filter->fmt_in.video.i_chroma;
> + vlc_fourcc_t output_chroma = filter->fmt_out.video.i_chroma;
> +
> + for (size_t i=0; i<ARRAY_SIZE(supported_chromas); ++i)
> + {
> + is_input_valid |= supported_chromas[i] == input_chroma;
> + is_output_valid |= supported_chromas[i] == output_chroma;
> + }
> +
> + /* If we don't convert from or to CVPX chroma, we don't need to use
> + * this filter at all. */
> + if (!is_input_valid && !is_output_valid)
> + return VLC_EGENERIC;
> +
> + /* If we convert from CVPX to CVPX, we can directly use the filter
> + * above without this one. */
> + if (is_input_valid && is_output_valid)
> + return VLC_EGENERIC;
> +
> + /* Store which side was in CVPixelBuffer chroma */
> + bool is_input_cvpx = is_input_valid;
> +
> + /* Check whether the other software chroma is supported. */
> + for (size_t i=0; i<ARRAY_SIZE(supported_sw_chromas); ++i)
> + {
> + is_input_valid |= supported_sw_chromas[i] == input_chroma;
> + is_output_valid |= supported_sw_chromas[i] == output_chroma;
> + }
> +
> + /* If one of the side is not true yet, it means we didn't found a
> matching
> + * software chroma and hardware chroma for this side. */
> + if (!is_input_valid || !is_output_valid)
> + return VLC_EGENERIC;
> +
> + msg_Dbg(obj, "Starting CVPX conversion chain %4.4s -> %4.4s",
> + (const char *)&input_chroma,
> + (const char *)&output_chroma);
> +
> + /* We create a filter chain to encapsulate the two converters. */
> + filter_chain_t *chain =
> + filter_chain_NewVideo(filter, false, &filter->owner);
> + if (chain == NULL)
> + return VLC_ENOMEM;
> +
> + filter_chain_Reset(chain, &filter->fmt_in, filter->vctx_in,
> &filter->fmt_out);
> +
> + /* Check whether we need to resize before or after the
> + * first conversion. */
> + es_format_t fmt_out;
> + if (is_input_cvpx)
> + es_format_Copy(&fmt_out, &filter->fmt_out);
> + else
> + es_format_Copy(&fmt_out, &filter->fmt_in);
> +
> + fmt_out.video.i_chroma
> + = fmt_out.i_codec
> + = GetIntermediateChroma(input_chroma, output_chroma);
> +
> + var_Create(filter, "cvpx-chroma-chain", VLC_VAR_BOOL);
> + var_SetBool(filter, "cvpx-chroma-chain", true);
> +
> + /* Append intermediate CVPX chroma */
> + ret = filter_chain_AppendConverter(chain, &fmt_out);
> + if (ret != 0)
> + goto error;
> + /* Append final chroma, either CVPX or software. */
> + ret = filter_chain_AppendConverter(chain, NULL);
> + if (ret != 0)
> + goto error;
> +
> + struct vlc_video_context *vctx_out =
> + filter_chain_GetVideoCtxOut(chain);
> +
> + filter->vctx_out = vctx_out;
> + filter->p_sys = chain;
> + filter->pf_flush = chain_CVPX_Flush;
> + filter->pf_video_filter = chain_CVPX_Filter;
> +
> + /* Display the current conversion chain in the logs. */
> + msg_Dbg(filter, "CVPX conversion chain:");
> + filter_chain_ForEach(chain, displayChain, NULL);
> +
> + return VLC_SUCCESS;
> +error:
> + msg_Err(filter, "Failed to insert converter for CVPX chain");
> + filter_chain_Delete(chain);
> + var_Destroy(filter, "cvpx-chroma-chain");
> + return VLC_EGENERIC;
> +}
> +
> +static void
> +Close_chain_CVPX(vlc_object_t *obj)
> +{
> + filter_t *filter = (filter_t*)obj;
> + filter_chain_t *chain = filter->p_sys;
> + filter_chain_Delete(chain);
> + var_Destroy(filter, "cvpx-chroma-chain");
LGTM
> +}
> +
> #endif
> --
> 2.27.0
>
> _______________________________________________
> vlc-devel mailing list
> To unsubscribe or modify your subscription options:
> https://mailman.videolan.org/listinfo/vlc-devel
More information about the vlc-devel
mailing list