Re: [FFmpeg-devel] [PATCH 1/5] libswscale: Re-factor ff_shuffle_filter_coefficients.

2022-02-16 Thread Michael Niedermayer
On Wed, Feb 09, 2022 at 10:09:45AM +0100, Alan Kelly wrote:
> Make the code more readable and follow the style guide.
> ---
>  libswscale/utils.c | 64 +++---
>  1 file changed, 37 insertions(+), 27 deletions(-)
> 
> diff --git a/libswscale/utils.c b/libswscale/utils.c
> index c5ea8853d5..1d919e863a 100644
> --- a/libswscale/utils.c
> +++ b/libswscale/utils.c
> @@ -278,39 +278,49 @@ static const FormatEntry format_entries[] = {
>  [AV_PIX_FMT_P416LE]  = { 1, 1 },
>  };
>  
> -void ff_shuffle_filter_coefficients(SwsContext *c, int *filterPos, int 
> filterSize, int16_t *filter, int dstW){
> +void ff_shuffle_filter_coefficients(SwsContext *c, int *filterPos,
> +   int filterSize, int16_t *filter,
> +   int dstW)
> +{
>  #if ARCH_X86_64
> -int i, j, k, l;
> +int i, j, k;
>  int cpu_flags = av_get_cpu_flags();
> +// avx2 hscale filter processes 16 pixel blocks.
> +if (!filter || dstW % 16 != 0)
> +return;
>  if (EXTERNAL_AVX2_FAST(cpu_flags) && !(cpu_flags & 
> AV_CPU_FLAG_SLOW_GATHER)) {
> -if ((c->srcBpc == 8) && (c->dstBpc <= 14)){
> -if (dstW % 16 == 0){
> -if (filter != NULL){
> -for (i = 0; i < dstW; i += 8){
> -FFSWAP(int, filterPos[i + 2], filterPos[i+4]);
> -FFSWAP(int, filterPos[i + 3], filterPos[i+5]);
> -}
> -if (filterSize > 4){
> -int16_t *tmp2 = av_malloc(dstW * filterSize * 2);
> -memcpy(tmp2, filter, dstW * filterSize * 2);
> -for (i = 0; i < dstW; i += 16){//pixel
> -for (k = 0; k < filterSize / 4; ++k){//fcoeff
> -for (j = 0; j < 16; ++j){//inner pixel
> -for (l = 0; l < 4; ++l){//coeff
> -int from = i * filterSize + j * 
> filterSize + k * 4 + l;
> -int to = (i) * filterSize + j * 4 + 
> l + k * 64;
> -filter[to] = tmp2[from];
> -}
> -}
> -}
> -}
> -av_free(tmp2);
> -}
> -}
> -}
> +if ((c->srcBpc == 8) && (c->dstBpc <= 14)) {
> +   int16_t *filterCopy = NULL;
> +   if (filterSize > 4) {

> +   if (!FF_ALLOC_TYPED_ARRAY(filterCopy, dstW * filterSize))
> +   return;

this is not a matter of style, it changes a null pointer dereference on error
to simply returning with no error handling. I know the next patches
change this again but that makes it just more messy


> +   memcpy(filterCopy, filter, dstW * filterSize * 
> sizeof(int16_t));
> +   }
> +   // Do not swap filterPos for pixels which won't be processed by
> +   // the main loop.
> +   for (i = 0; i + 8 <= dstW; i += 8) {
> +   FFSWAP(int, filterPos[i + 2], filterPos[i + 4]);
> +   FFSWAP(int, filterPos[i + 3], filterPos[i + 5]);
> +   }
> +   if (filterSize > 4) {
> +   // 16 pixels are processed at a time.
> +   for (i = 0; i + 16 <= dstW; i += 16) {
> +   // 4 filter coeffs are processed at a time.
> +   for (k = 0; k + 4 <= filterSize; k += 4) {
> +   for (j = 0; j < 16; ++j) {
> +   int from = (i + j) * filterSize + k;
> +   int to = i * filterSize + j * 4 + k * 16;
> +   memcpy([to], [from], 4 * 
> sizeof(int16_t));
> +   }
> +   }
> +   }
> +   }

> +   if (filterCopy)
> +   av_free(filterCopy);

The null check is unneeded


[...]
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[FFmpeg-devel] [PATCH 1/5] libswscale: Re-factor ff_shuffle_filter_coefficients.

2022-02-09 Thread Alan Kelly
Make the code more readable and follow the style guide.
---
 libswscale/utils.c | 64 +++---
 1 file changed, 37 insertions(+), 27 deletions(-)

diff --git a/libswscale/utils.c b/libswscale/utils.c
index c5ea8853d5..1d919e863a 100644
--- a/libswscale/utils.c
+++ b/libswscale/utils.c
@@ -278,39 +278,49 @@ static const FormatEntry format_entries[] = {
 [AV_PIX_FMT_P416LE]  = { 1, 1 },
 };
 
-void ff_shuffle_filter_coefficients(SwsContext *c, int *filterPos, int 
filterSize, int16_t *filter, int dstW){
+void ff_shuffle_filter_coefficients(SwsContext *c, int *filterPos,
+   int filterSize, int16_t *filter,
+   int dstW)
+{
 #if ARCH_X86_64
-int i, j, k, l;
+int i, j, k;
 int cpu_flags = av_get_cpu_flags();
+// avx2 hscale filter processes 16 pixel blocks.
+if (!filter || dstW % 16 != 0)
+return;
 if (EXTERNAL_AVX2_FAST(cpu_flags) && !(cpu_flags & 
AV_CPU_FLAG_SLOW_GATHER)) {
-if ((c->srcBpc == 8) && (c->dstBpc <= 14)){
-if (dstW % 16 == 0){
-if (filter != NULL){
-for (i = 0; i < dstW; i += 8){
-FFSWAP(int, filterPos[i + 2], filterPos[i+4]);
-FFSWAP(int, filterPos[i + 3], filterPos[i+5]);
-}
-if (filterSize > 4){
-int16_t *tmp2 = av_malloc(dstW * filterSize * 2);
-memcpy(tmp2, filter, dstW * filterSize * 2);
-for (i = 0; i < dstW; i += 16){//pixel
-for (k = 0; k < filterSize / 4; ++k){//fcoeff
-for (j = 0; j < 16; ++j){//inner pixel
-for (l = 0; l < 4; ++l){//coeff
-int from = i * filterSize + j * 
filterSize + k * 4 + l;
-int to = (i) * filterSize + j * 4 + l 
+ k * 64;
-filter[to] = tmp2[from];
-}
-}
-}
-}
-av_free(tmp2);
-}
-}
-}
+if ((c->srcBpc == 8) && (c->dstBpc <= 14)) {
+   int16_t *filterCopy = NULL;
+   if (filterSize > 4) {
+   if (!FF_ALLOC_TYPED_ARRAY(filterCopy, dstW * filterSize))
+   return;
+   memcpy(filterCopy, filter, dstW * filterSize * sizeof(int16_t));
+   }
+   // Do not swap filterPos for pixels which won't be processed by
+   // the main loop.
+   for (i = 0; i + 8 <= dstW; i += 8) {
+   FFSWAP(int, filterPos[i + 2], filterPos[i + 4]);
+   FFSWAP(int, filterPos[i + 3], filterPos[i + 5]);
+   }
+   if (filterSize > 4) {
+   // 16 pixels are processed at a time.
+   for (i = 0; i + 16 <= dstW; i += 16) {
+   // 4 filter coeffs are processed at a time.
+   for (k = 0; k + 4 <= filterSize; k += 4) {
+   for (j = 0; j < 16; ++j) {
+   int from = (i + j) * filterSize + k;
+   int to = i * filterSize + j * 4 + k * 16;
+   memcpy([to], [from], 4 * 
sizeof(int16_t));
+   }
+   }
+   }
+   }
+   if (filterCopy)
+   av_free(filterCopy);
 }
 }
 #endif
+return;
 }
 
 int sws_isSupportedInput(enum AVPixelFormat pix_fmt)
-- 
2.35.0.263.gb82422642f-goog

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