From: Niklas Haas <g...@haasn.dev>
This handles the low-level execution of an op list, and integration into
the SwsGraph infrastructure. To handle frames with insufficient padding in
the stride (or a width smaller than one block size), we use a fallback loop
that pads the last column of pixels using `memcpy` into an appropriately
sized buffer.
---
libswscale/ops.c | 256 +++++++++++++++++++++++++++++++++++++++++++++++
libswscale/ops.h | 14 +++
2 files changed, 270 insertions(+)
diff --git a/libswscale/ops.c b/libswscale/ops.c
index 8491bd9cad..d466f5e45c 100644
--- a/libswscale/ops.c
+++ b/libswscale/ops.c
@@ -582,3 +582,259 @@ int ff_sws_ops_compile(SwsContext *ctx, const SwsOpList
*ops, SwsCompiledOp *out
ff_sws_op_list_print(ctx, AV_LOG_WARNING, ops);
return AVERROR(ENOTSUP);
}
+
+typedef struct SwsOpPass {
+ SwsCompiledOp comp;
+ SwsOpExec exec_base;
+ int num_blocks;
+ int tail_off_in;
+ int tail_off_out;
+ int tail_size_in;
+ int tail_size_out;
+ bool memcpy_in;
+ bool memcpy_out;
+} SwsOpPass;
+
+static void op_pass_free(void *ptr)
+{
+ SwsOpPass *p = ptr;
+ if (!p)
+ return;
+
+ if (p->comp.free)
+ p->comp.free(p->comp.priv);
+
+ av_free(p);
+}
+
+static void op_pass_setup(const SwsImg *out, const SwsImg *in, const SwsPass
*pass)
+{
+ const AVPixFmtDescriptor *indesc = av_pix_fmt_desc_get(in->fmt);
+ const AVPixFmtDescriptor *outdesc = av_pix_fmt_desc_get(out->fmt);
+
+ SwsOpPass *p = pass->priv;
+ SwsOpExec *exec = &p->exec_base;
+ const SwsCompiledOp *comp = &p->comp;
+ const int block_size = comp->block_size;
+ p->num_blocks = (pass->width + block_size - 1) / block_size;
+
+ /* Set up main loop parameters */
+ const int aligned_w = p->num_blocks * block_size;
+ const int safe_width = (p->num_blocks - 1) * block_size;
+ const int tail_size = pass->width - safe_width;
+ p->tail_off_in = safe_width * exec->pixel_bits_in >> 3;
+ p->tail_off_out = safe_width * exec->pixel_bits_out >> 3;
+ p->tail_size_in = tail_size * exec->pixel_bits_in >> 3;
+ p->tail_size_out = tail_size * exec->pixel_bits_out >> 3;
+ p->memcpy_in = false;
+ p->memcpy_out = false;
+
+ for (int i = 0; i < 4 && in->data[i]; i++) {
+ const int sub_x = (i == 1 || i == 2) ? indesc->log2_chroma_w : 0;
+ const int plane_w = (aligned_w + sub_x) >> sub_x;
+ const int plane_pad = (comp->over_read + sub_x) >> sub_x;
+ const int plane_size = plane_w * exec->pixel_bits_in >> 3;
+ p->memcpy_in |= plane_size + plane_pad > in->linesize[i];
+ exec->in_stride[i] = in->linesize[i];
+ }
+
+ for (int i = 0; i < 4 && out->data[i]; i++) {
+ const int sub_x = (i == 1 || i == 2) ? outdesc->log2_chroma_w : 0;
+ const int plane_w = (aligned_w + sub_x) >> sub_x;
+ const int plane_pad = (comp->over_write + sub_x) >> sub_x;
+ const int plane_size = plane_w * exec->pixel_bits_out >> 3;
+ p->memcpy_out |= plane_size + plane_pad > out->linesize[i];
+ exec->out_stride[i] = out->linesize[i];
+ }
+}
+
+/* Dispatch kernel over the last column of the image using memcpy */
+static av_always_inline void
+handle_tail(const SwsOpPass *p, SwsOpExec *exec,
+ const SwsImg *out_base, const bool copy_out,
+ const SwsImg *in_base, const bool copy_in,
+ int y, const int h)
+{
+ DECLARE_ALIGNED_64(uint8_t, tmp)[2][4][sizeof(uint32_t[128])];
+
+ const SwsCompiledOp *comp = &p->comp;
+ const int tail_size_in = p->tail_size_in;
+ const int tail_size_out = p->tail_size_out;
+ const int bx = p->num_blocks - 1;
+
+ SwsImg in = ff_sws_img_shift(in_base, y);
+ SwsImg out = ff_sws_img_shift(out_base, y);
+ for (int i = 0; i < 4 && in.data[i]; i++) {
+ in.data[i] += p->tail_off_in;
+ if (copy_in) {
+ exec->in[i] = (void *) tmp[0][i];
+ exec->in_stride[i] = sizeof(tmp[0][i]);
+ } else {
+ exec->in[i] = in.data[i];
+ }
+ }
+
+ for (int i = 0; i < 4 && out.data[i]; i++) {
+ out.data[i] += p->tail_off_out;
+ if (copy_out) {
+ exec->out[i] = (void *) tmp[1][i];
+ exec->out_stride[i] = sizeof(tmp[1][i]);
+ } else {
+ exec->out[i] = out.data[i];
+ }
+ }
+
+ for (int y_end = y + h; y < y_end; y++) {
+ if (copy_in) {
+ for (int i = 0; i < 4 && in.data[i]; i++) {
+ av_assert2(tmp[0][i] + tail_size_in < (uint8_t *) tmp[1]);
+ memcpy(tmp[0][i], in.data[i], tail_size_in);
+ in.data[i] += in.linesize[i];
+ }
+ }
+
+ comp->func(exec, comp->priv, bx, y, p->num_blocks, y + 1);
+
+ if (copy_out) {
+ for (int i = 0; i < 4 && out.data[i]; i++) {
+ av_assert2(tmp[1][i] + tail_size_out < (uint8_t *) tmp[2]);
+ memcpy(out.data[i], tmp[1][i], tail_size_out);
+ out.data[i] += out.linesize[i];
+ }
+ }
+
+ for (int i = 0; i < 4; i++) {
+ if (!copy_in)
+ exec->in[i] += in.linesize[i];
+ if (!copy_out)
+ exec->out[i] += out.linesize[i];
+ }
+ }
+}
+
+static void op_pass_run(const SwsImg *out_base, const SwsImg *in_base,
+ const int y, const int h, const SwsPass *pass)
+{
+ const SwsOpPass *p = pass->priv;
+ const SwsCompiledOp *comp = &p->comp;
+
+ /* Fill exec metadata for this slice */
+ const SwsImg in = ff_sws_img_shift(in_base, y);
+ const SwsImg out = ff_sws_img_shift(out_base, y);
+ SwsOpExec exec = p->exec_base;
+ exec.slice_y = y;
+ exec.slice_h = h;
+ for (int i = 0; i < 4; i++) {
+ exec.in[i] = in.data[i];
+ exec.out[i] = out.data[i];
+ }
+
+ /**
+ * To ensure safety, we need to consider the following:
+ *
+ * 1. We can overread the input, unless this is the last line of an
+ * unpadded buffer. All defined operations can handle arbitrary pixel
+ * input, so overread of arbitrary data is fine.
+ *
+ * 2. We can overwrite the output, as long as we don't write more than the
+ * amount of pixels that fit into one linesize. So we always need to
+ * memcpy the last column on the output side if unpadded.
+ *
+ * 3. For the last row, we also need to memcpy the remainder of the input,
+ * to avoid reading past the end of the buffer. Note that since we know
+ * the run() function is called on stripes of the same buffer, we don't
+ * need to worry about this for the end of a slice.
+ */
+
+ const int last_slice = y + h == pass->height;
+ const bool memcpy_in = last_slice && p->memcpy_in;
+ const bool memcpy_out = p->memcpy_out;
+ const int num_blocks = p->num_blocks;
+ const int blocks_main = num_blocks - memcpy_out;
+ const int h_main = h - memcpy_in;
+
+ /* Handle main section */
+ comp->func(&exec, comp->priv, 0, y, blocks_main, y + h_main);
+
+ if (memcpy_in) {
+ /* Safe part of last row */
+ for (int i = 0; i < 4; i++) {
+ exec.in[i] += h_main * in.linesize[i];
+ exec.out[i] += h_main * out.linesize[i];
+ }
+ comp->func(&exec, comp->priv, 0, y + h_main, num_blocks - 1, y + h);
+ }
+
+ /* Handle last column via memcpy, takes over `exec` so call these last */
+ if (memcpy_out)
+ handle_tail(p, &exec, out_base, true, in_base, false, y, h_main);
+ if (memcpy_in)
+ handle_tail(p, &exec, out_base, memcpy_out, in_base, true, y + h_main,
1);
+}
+
+static int rw_pixel_bits(const SwsOp *op)
+{
+ const int elems = op->rw.packed ? op->rw.elems : 1;
+ const int size = ff_sws_pixel_type_size(op->type);
+ const int bits = 8 >> op->rw.frac;
+ av_assert1(bits >= 1);
+ return elems * size * bits;
+}
+
+int ff_sws_compile_pass(SwsGraph *graph, SwsOpList *ops, int flags, SwsFormat
dst,
+ SwsPass *input, SwsPass **output)
+{
+ SwsContext *ctx = graph->ctx;
+ SwsOpPass *p = NULL;
+ const SwsOp *read = &ops->ops[0];
+ const SwsOp *write = &ops->ops[ops->num_ops - 1];
+ SwsPass *pass;
+ int ret;
+
+ if (ops->num_ops < 2) {
+ av_log(ctx, AV_LOG_ERROR, "Need at least two operations.\n");
+ return AVERROR(EINVAL);
+ }
+
+ if (read->op != SWS_OP_READ || write->op != SWS_OP_WRITE) {
+ av_log(ctx, AV_LOG_ERROR, "First and last operations must be a read "
+ "and write, respectively.\n");
+ return AVERROR(EINVAL);
+ }
+
+ if (flags & SWS_OP_FLAG_OPTIMIZE)
+ RET(ff_sws_op_list_optimize(ops));
+ else
+ ff_sws_op_list_update_comps(ops);
+
+ p = av_mallocz(sizeof(*p));
+ if (!p)
+ return AVERROR(ENOMEM);
+
+ p->exec_base = (SwsOpExec) {
+ .width = dst.width,
+ .height = dst.height,
+ .pixel_bits_in = rw_pixel_bits(read),
+ .pixel_bits_out = rw_pixel_bits(write),
+ };
+
+ ret = ff_sws_ops_compile(ctx, ops, &p->comp);
+ if (ret < 0)
+ goto fail;
+
+ pass = ff_sws_graph_add_pass(graph, dst.format, dst.width, dst.height,
input,
+ 1, p, op_pass_run);
+ if (!pass) {
+ ret = AVERROR(ENOMEM);
+ goto fail;
+ }
+ pass->setup = op_pass_setup;
+ pass->free = op_pass_free;
+
+ *output = pass;
+ return 0;
+
+fail:
+ op_pass_free(p);
+ return ret;
+}
diff --git a/libswscale/ops.h b/libswscale/ops.h
index ae65d578b3..1a992f42ec 100644
--- a/libswscale/ops.h
+++ b/libswscale/ops.h
@@ -249,4 +249,18 @@ void ff_sws_op_list_update_comps(SwsOpList *ops);
*/
int ff_sws_op_list_optimize(SwsOpList *ops);
+enum SwsOpCompileFlags {
+ /* Automatically optimize the operations when compiling */
+ SWS_OP_FLAG_OPTIMIZE = 1 << 0,
+};
+
+/**
+ * Resolves an operation list to a graph pass. The first and last operations
+ * must be a read/write respectively. `flags` is a list of SwsOpCompileFlags.
+ *
+ * Note: `ops` may be modified by this function.
+ */
+int ff_sws_compile_pass(SwsGraph *graph, SwsOpList *ops, int flags, SwsFormat
dst,
+ SwsPass *input, SwsPass **output);
+
#endif
--
2.49.0
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