[FFmpeg-devel] [PATCH v3 1/2] vf_crop: Add support for cropping hardware frames
Song, Ruiling
ruiling.song at intel.com
Tue Mar 26 12:59:14 EET 2019
> -----Original Message-----
> From: ffmpeg-devel [mailto:ffmpeg-devel-bounces at ffmpeg.org] On Behalf Of
> Mark Thompson
> Sent: Sunday, March 24, 2019 12:19 AM
> To: ffmpeg-devel at ffmpeg.org
> Subject: [FFmpeg-devel] [PATCH v3 1/2] vf_crop: Add support for cropping
> hardware frames
>
> Set the cropping fields in the AVFrame.
> ---
> libavfilter/vf_crop.c | 74 +++++++++++++++++++++++++++++--------------
> 1 file changed, 51 insertions(+), 23 deletions(-)
>
> There is the slightly unfortunate effect the filter links don't carry the cropping
> information, so we don't know how big the cropped output is in following links
> until we actually get a frame.
>
> For example, to get the middle ninth of a stream:
>
> ./ffmpeg_g -y -hwaccel vaapi -hwaccel_device /dev/dri/renderD128 -
> hwaccel_output_format vaapi -i in.mp4 -an -vf
> "crop=iw/3:ih/3:iw/3:ih/3,scale_vaapi=iw/3:ih/3" -c:v h264_vaapi out.mp4
Hi Mark,
I tested the command against the patch, it works.
But for people who have no idea of implementation details, I think the ”scale_vaapi=iw/3:ih/3“ will be very confusing.
I think we need to make scale_vaapi evaluate input dimensions considering crop information. What do you think?
People would just think that the input buffer to the scale_vaapi is the cropped size.
And do we need to add warning message against crop information in encoder if user failed to add some vaapi filter after crop?
Seems that vaapi encoder does not encode correctly with crop?
Thanks!
Ruiling
>
> Without the extra arguments to scale it will take the cropped part correctly but
> then scale it to the original size.
>
> diff --git a/libavfilter/vf_crop.c b/libavfilter/vf_crop.c
> index 84be4c7d0d..7f6b0f03d3 100644
> --- a/libavfilter/vf_crop.c
> +++ b/libavfilter/vf_crop.c
> @@ -98,9 +98,17 @@ static int query_formats(AVFilterContext *ctx)
>
> for (fmt = 0; av_pix_fmt_desc_get(fmt); fmt++) {
> const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(fmt);
> - if (!(desc->flags & (AV_PIX_FMT_FLAG_HWACCEL |
> AV_PIX_FMT_FLAG_BITSTREAM)) &&
> - !((desc->log2_chroma_w || desc->log2_chroma_h) && !(desc->flags &
> AV_PIX_FMT_FLAG_PLANAR)) &&
> - (ret = ff_add_format(&formats, fmt)) < 0)
> + if (desc->flags & AV_PIX_FMT_FLAG_BITSTREAM)
> + continue;
> + if (!(desc->flags & AV_PIX_FMT_FLAG_HWACCEL)) {
> + // Not usable if there is any subsampling but the format is
> + // not planar (e.g. YUYV422).
> + if ((desc->log2_chroma_w || desc->log2_chroma_h) &&
> + !(desc->flags & AV_PIX_FMT_FLAG_PLANAR))
> + continue;
> + }
> + ret = ff_add_format(&formats, fmt);
> + if (ret < 0)
> return ret;
> }
>
> @@ -157,8 +165,14 @@ static int config_input(AVFilterLink *link)
> s->var_values[VAR_POS] = NAN;
>
> av_image_fill_max_pixsteps(s->max_step, NULL, pix_desc);
> - s->hsub = pix_desc->log2_chroma_w;
> - s->vsub = pix_desc->log2_chroma_h;
> +
> + if (pix_desc->flags & AV_PIX_FMT_FLAG_HWACCEL) {
> + s->hsub = 1;
> + s->vsub = 1;
> + } else {
> + s->hsub = pix_desc->log2_chroma_w;
> + s->vsub = pix_desc->log2_chroma_h;
> + }
>
> if ((ret = av_expr_parse_and_eval(&res, (expr = s->w_expr),
> var_names, s->var_values,
> @@ -237,9 +251,15 @@ fail_expr:
> static int config_output(AVFilterLink *link)
> {
> CropContext *s = link->src->priv;
> + const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(link->format);
>
> - link->w = s->w;
> - link->h = s->h;
> + if (desc->flags & AV_PIX_FMT_FLAG_HWACCEL) {
> + // Hardware frames adjust the cropping regions rather than
> + // changing the frame size.
> + } else {
> + link->w = s->w;
> + link->h = s->h;
> + }
> link->sample_aspect_ratio = s->out_sar;
>
> return 0;
> @@ -252,9 +272,6 @@ static int filter_frame(AVFilterLink *link, AVFrame
> *frame)
> const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(link->format);
> int i;
>
> - frame->width = s->w;
> - frame->height = s->h;
> -
> s->var_values[VAR_N] = link->frame_count_out;
> s->var_values[VAR_T] = frame->pts == AV_NOPTS_VALUE ?
> NAN : frame->pts * av_q2d(link->time_base);
> @@ -285,22 +302,33 @@ static int filter_frame(AVFilterLink *link, AVFrame
> *frame)
> (int)s->var_values[VAR_N], s->var_values[VAR_T], s-
> >var_values[VAR_POS],
> s->x, s->y, s->x+s->w, s->y+s->h);
>
> - frame->data[0] += s->y * frame->linesize[0];
> - frame->data[0] += s->x * s->max_step[0];
> -
> - if (!(desc->flags & AV_PIX_FMT_FLAG_PAL || desc->flags & FF_PSEUDOPAL))
> {
> - for (i = 1; i < 3; i ++) {
> - if (frame->data[i]) {
> - frame->data[i] += (s->y >> s->vsub) * frame->linesize[i];
> - frame->data[i] += (s->x * s->max_step[i]) >> s->hsub;
> + if (desc->flags & AV_PIX_FMT_FLAG_HWACCEL) {
> + frame->crop_top += s->y;
> + frame->crop_left += s->x;
> + frame->crop_bottom = frame->height - frame->crop_top - frame-
> >crop_bottom - s->h;
> + frame->crop_right = frame->width - frame->crop_left - frame-
> >crop_right - s->w;
> +
> + } else {
> + frame->width = s->w;
> + frame->height = s->h;
> +
> + frame->data[0] += s->y * frame->linesize[0];
> + frame->data[0] += s->x * s->max_step[0];
> +
> + if (!(desc->flags & AV_PIX_FMT_FLAG_PAL || desc->flags &
> FF_PSEUDOPAL)) {
> + for (i = 1; i < 3; i ++) {
> + if (frame->data[i]) {
> + frame->data[i] += (s->y >> s->vsub) * frame->linesize[i];
> + frame->data[i] += (s->x * s->max_step[i]) >> s->hsub;
> + }
> }
> }
> - }
>
> - /* alpha plane */
> - if (frame->data[3]) {
> - frame->data[3] += s->y * frame->linesize[3];
> - frame->data[3] += s->x * s->max_step[3];
> + /* alpha plane */
> + if (frame->data[3]) {
> + frame->data[3] += s->y * frame->linesize[3];
> + frame->data[3] += s->x * s->max_step[3];
> + }
> }
>
> return ff_filter_frame(link->dst->outputs[0], frame);
> --
> 2.19.2
>
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