[FFmpeg-devel] [PATCH v2 02/19] swscale: rename SwsContext to SwsInternal

Michael Niedermayer michael at niedermayer.cc
Sun Oct 20 00:37:17 EEST 2024


On Thu, Oct 17, 2024 at 02:28:54PM +0200, Niklas Haas wrote:
> On Mon, 14 Oct 2024 20:58:31 +0200 Michael Niedermayer <michael at niedermayer.cc> wrote:
> > On Mon, Oct 14, 2024 at 08:33:50PM +0200, Niklas Haas wrote:
> > > On Mon, 14 Oct 2024 19:49:21 +0200 Michael Niedermayer <michael at niedermayer.cc> wrote:
> > > > On Mon, Oct 14, 2024 at 06:39:21PM +0200, Michael Niedermayer wrote:
> > > > > On Mon, Oct 14, 2024 at 06:02:45PM +0200, Niklas Haas wrote:
> > > > > > On Mon, 14 Oct 2024 16:55:39 +0200 Michael Niedermayer <michael at niedermayer.cc> wrote:
> > > > > > > On Mon, Oct 14, 2024 at 03:37:27PM +0200, Niklas Haas wrote:
> > > > > > > > From: Niklas Haas <git at haasn.dev>
> > > > > > > >
> > > > > > > > And preserve the public SwsContext as separate name. The motivation here
> > > > > > > > is that I want to turn SwsContext into a public struct, while keeping the
> > > > > > > > internal implementation hidden. Additionally, I also want to be able to
> > > > > > > > use multiple internal implementations, e.g. for GPU devices.
> > > > > > > >
> > > > > > > > This commit does not include any functional changes. For the most part, it is
> > > > > > > > a simple rename. The only complications arise from the public facing API
> > > > > > > > functions, which preserve their current type (and hence require an additional
> > > > > > > > unwrapping step internally), and the checkasm test framework, which directly
> > > > > > > > accesses SwsInternal.
> > > > > > > >
> > > > > > > > For consistency, the affected functions that need to maintain a distionction
> > > > > > > > have generally been changed to refer to the SwsContext as *sws, and the
> > > > > > > > SwsInternal as *c.
> > > > > > > >
> > > > > > > > In an upcoming commit, I will provide a backing definition for the public
> > > > > > > > SwsContext, and update `sws_internal()` to dereference the internal struct
> > > > > > > > instead of merely casting it.
> > > > > > > >
> > > > > > > > Sponsored-by: Sovereign Tech Fund
> > > > > > > > Signed-off-by: Niklas Haas <git at haasn.dev>
> > > > > > >
> > > > > > > does not apply
> > > > > > >
> > > > > > >
> > > > > > > Applying: swscale: rename SwsContext to SwsInternal
> > > > > > > Using index info to reconstruct a base tree...
> > > > > > > M	libswscale/output.c
> > > > > > > M	libswscale/utils.c
> > > > > > > Falling back to patching base and 3-way merge...
> > > > > > > Auto-merging libswscale/utils.c
> > > > > > > Auto-merging libswscale/output.c
> > > > > > > CONFLICT (content): Merge conflict in libswscale/output.c
> > > > > > > error: Failed to merge in the changes.
> > > > > > > Patch failed at 0001 swscale: rename SwsContext to SwsInternal
> > > > > > > hint: Use 'git am --show-current-patch=diff' to see the failed patch
> > > > > > > hint: When you have resolved this problem, run "git am --continue".
> > > > > > > hint: If you prefer to skip this patch, run "git am --skip" instead.
> > > > > > > hint: To restore the original branch and stop patching, run "git am --abort".
> > > > > > > hint: Disable this message with "git config advice.mergeConflict false"
> > > > > > >
> > > > > > > thx
> > > > > >
> > > > > > I've rebased it here:
> > > > > >
> > > > > > https://github.com/haasn/FFmpeg/tree/swscale4
> > > > >
> > > > > on x86-32 linux
> > > > >
> > > > > make
> > > > > CC	libswscale/alphablend.o
> > > > > In file included from src/libavutil/internal.h:39:0,
> > > > >                  from src/libavutil/common.h:50,
> > > > >                  from src/libavutil/avutil.h:301,
> > > > >                  from src/libswscale/swscale.h:33,
> > > > >                  from src/libswscale/swscale_internal.h:28,
> > > > >                  from src/libswscale/alphablend.c:21:
> > > > > src/libswscale/swscale_internal.h:682:1: error: static assertion failed: "yuv2rgb_y_offset must be updated in x86 asm"
> > > > >  static_assert(offsetof(SwsInternal, yuv2rgb_y_offset) == 40348,
> > > > >  ^
> > > > > make: *** [src/ffbuild/common.mak:81: libswscale/alphablend.o] Error 1
> > > >
> > > > and on qemu-MIPS: (big endian issue maybe)
> > > >
> > > > --- src/tests/ref/fate/sws-yuv-colorspace	2024-10-14 18:05:24.495328917 +0200
> > > > +++ tests/data/fate/sws-yuv-colorspace	2024-10-14 18:41:48.656863487 +0200
> > > > @@ -3,4 +3,4 @@
> > > >  #codec_id 0: rawvideo
> > > >  #dimensions 0: 352x288
> > > >  #sar 0: 0/1
> > > > -0,          0,          0,        1,   152064, 0xcbcb97b9
> > > > +0,          0,          0,        1,   152064, 0x956698d5
> > > > TEST    acodec-pcm-u8
> > > > Test sws-yuv-colorspace failed. Look at tests/data/fate/sws-yuv-colorspace.err for
> > >
> > > Do you have a command line I could copy to reproduce this?
> >
> > iam not sure what you ask, what i use to cross build ffmpeg to mips and run it
> > under qemu is below, but this is not the latest qemu or latest compilers. I tend
> > to only update these when i have to or when something breaks
> >
> > ../configure --target-exec='qemu-mips -cpu 74Kf -L /usr/mips-linux-gnu/ /usr/mips-linux-gnu/lib/ld-2.30.so --inhibit-cache' --samples=fate-suite/ --enable-gpl --cross-prefix=/usr/mips-linux-gnu/bin/ --cc='ccache mips-linux-gnu-gcc-7' --arch=mips --target-os=linux --enable-cross-compile --disable-mipsfpu --disable-iconv --cpu=74Kf
> >
> > this is on ubuntu
> 
> Fixed, thanks. The int64_t flags were being dereferenced as `unsigned int` by
> the AVOption code, which broke on big endian platforms.
> 
> Pushed the fix to https://github.com/haasn/FFmpeg/tree/swscale4

Both swscale4 and swscale5 fail if used a bit differently from ffmpeg
simple testcase with DC color below
(also feel free to add this to the fate tests, if you like)

no-scale rgb-lim rgb-lim  200 -> 200
no-scale rgb-lim rgb-ful  200 -> 200
no-scale rgb-ful rgb-lim  200 -> 200
no-scale rgb-ful rgb-ful  200 -> 200
no-scale rgb-lim yuv-lim  200 -> 16 FAIL
no-scale rgb-lim yuv-ful  200 -> 16 FAIL
no-scale rgb-ful yuv-lim  200 -> 16 FAIL
no-scale rgb-ful yuv-ful  200 -> 16 FAIL
no-scale yuv-lim rgb-lim  188 -> 0 FAIL
no-scale yuv-lim rgb-ful  188 -> 0 FAIL
no-scale yuv-ful rgb-lim  200 -> 0 FAIL
no-scale yuv-ful rgb-ful  200 -> 0 FAIL
no-scale yuv-lim yuv-lim  188 -> 188
no-scale yuv-lim yuv-ful  188 -> 188 FAIL
no-scale yuv-ful yuv-lim  200 -> 200 FAIL
no-scale yuv-ful yuv-ful  200 -> 200

scale    rgb-lim rgb-lim  200 -> 0 FAIL
scale    rgb-lim rgb-ful  200 -> 0 FAIL
scale    rgb-ful rgb-lim  200 -> 0 FAIL
scale    rgb-ful rgb-ful  200 -> 0 FAIL
scale    rgb-lim yuv-lim  200 -> 16 FAIL
scale    rgb-lim yuv-ful  200 -> 16 FAIL
scale    rgb-ful yuv-lim  200 -> 16 FAIL
scale    rgb-ful yuv-ful  200 -> 16 FAIL
scale    yuv-lim rgb-lim  188 -> 0 FAIL
scale    yuv-lim rgb-ful  188 -> 0 FAIL
scale    yuv-ful rgb-lim  200 -> 0 FAIL
scale    yuv-ful rgb-ful  200 -> 0 FAIL
scale    yuv-lim yuv-lim  188 -> 188
scale    yuv-lim yuv-ful  188 -> 188 FAIL
scale    yuv-ful yuv-lim  200 -> 200 FAIL
scale    yuv-ful yuv-ful  200 -> 200

vs:
no-scale rgb-lim rgb-lim  200 -> 200
no-scale rgb-lim rgb-ful  200 -> 200
no-scale rgb-ful rgb-lim  200 -> 200
no-scale rgb-ful rgb-ful  200 -> 200
no-scale rgb-lim yuv-lim  200 -> 188
no-scale rgb-lim yuv-ful  200 -> 200
no-scale rgb-ful yuv-lim  200 -> 188
no-scale rgb-ful yuv-ful  200 -> 200
no-scale yuv-lim rgb-lim  188 -> 200
no-scale yuv-lim rgb-ful  188 -> 200
no-scale yuv-ful rgb-lim  200 -> 200
no-scale yuv-ful rgb-ful  200 -> 200
no-scale yuv-lim yuv-lim  188 -> 188
no-scale yuv-lim yuv-ful  188 -> 200
no-scale yuv-ful yuv-lim  200 -> 188
no-scale yuv-ful yuv-ful  200 -> 200

scale    rgb-lim rgb-lim  200 -> 200
scale    rgb-lim rgb-ful  200 -> 200
scale    rgb-ful rgb-lim  200 -> 200
scale    rgb-ful rgb-ful  200 -> 200
scale    rgb-lim yuv-lim  200 -> 188
scale    rgb-lim yuv-ful  200 -> 200
scale    rgb-ful yuv-lim  200 -> 188
scale    rgb-ful yuv-ful  200 -> 200
scale    yuv-lim rgb-lim  188 -> 200
scale    yuv-lim rgb-ful  188 -> 200
scale    yuv-ful rgb-lim  200 -> 200
scale    yuv-ful rgb-ful  200 -> 200
scale    yuv-lim yuv-lim  188 -> 188
scale    yuv-lim yuv-ful  188 -> 200
scale    yuv-ful yuv-lim  200 -> 188
scale    yuv-ful yuv-ful  200 -> 200

#include <inttypes.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include "libswscale/swscale.h"
#include "libavutil/opt.h"
#include "libavutil/pixfmt.h"

#define W 128
#define H 128
#define STRIDE_YUV W
#define STRIDE_RGBA (W * 4)

void scale(uint8_t *dst[3], uint8_t *src[3], int s_yuv, int s_range,
           int d_yuv, int d_range, int scale)
{
    struct SwsContext *sws = sws_alloc_context();

    int exact = SWS_FULL_CHR_H_INT | SWS_FULL_CHR_H_INP |
                SWS_ACCURATE_RND | SWS_BITEXACT;
    av_opt_set_int(sws, "sws_flags", exact | SWS_POINT /* | SWS_PRINT_INFO*/, 0);

    av_opt_set_int(sws, "srcw", W, 0);
    av_opt_set_int(sws, "srch", H, 0);
    av_opt_set_int(sws, "src_format", s_yuv ? AV_PIX_FMT_YUV444P : AV_PIX_FMT_RGBA, 0);

    av_opt_set_int(sws, "dstw", scale ? W/2 : W, 0);
    av_opt_set_int(sws, "dsth", scale ? H/2 : H, 0);
    av_opt_set_int(sws, "dst_format", d_yuv ? AV_PIX_FMT_YUV444P : AV_PIX_FMT_RGBA, 0);

    sws_setColorspaceDetails(sws, sws_getCoefficients(SWS_CS_ITU709), !!s_range,
                             sws_getCoefficients(SWS_CS_ITU709), !!d_range,
                             0, 1 << 16, 1 << 16);

    int res = sws_init_context(sws, NULL, NULL);
    assert(res >= 0);

    int s_stride = s_yuv ? STRIDE_YUV : STRIDE_RGBA;
    int d_stride = d_yuv ? STRIDE_YUV : STRIDE_RGBA;
    int s_stride_a[3] = {s_stride, s_stride, s_stride};
    int d_stride_a[3] = {d_stride, d_stride, d_stride};
    sws_scale(sws, (const unsigned char *const *)src, s_stride_a, 0, H, dst, d_stride_a);
    sws_freeContext(sws);
}

void set_white(uint8_t *c[3], bool yuv, int val)
{
    if (yuv) {
        memset(c[0], val, STRIDE_YUV * H);
        memset(c[1], 128, STRIDE_YUV * H);
        memset(c[2], 128, STRIDE_YUV * H);
    } else {
        int i;
        memset(c[0], val, STRIDE_RGBA * H);
        for (i = 3; i<STRIDE_RGBA*H; i+=4)
            c[0][i] = 0xFF;
    }
}

int get_white(uint8_t *c[3], bool yuv)
{
    if (yuv) {
        return c[0][W/4 + STRIDE_YUV * (H/4)];
    } else {
        return c[0][W/4 * 4 + STRIDE_RGBA * (H/4) + 1];
    }
}

uint8_t *a[3], *b[3];

void test(unsigned int mode)
{
    bool d_range = mode & 1;
    bool d_yuv = mode & 4;
    bool s_range = mode & 2;
    bool s_yuv = mode & 8;
    bool doscale = mode & 16;
    bool lower = mode & 32;


    int ival = (s_yuv && !s_range) ? 188 : 200;

    set_white(a, s_yuv, ival);
    scale(b, a, s_yuv, s_range, d_yuv, d_range, doscale);
    int oval = get_white(b, d_yuv);
    printf("%-9s", doscale ? "scale" : "no-scale");
    printf("%s", s_yuv ? "yuv" : "rgb");
    printf("-%s ", s_range ? "ful" : "lim");
    printf("%s", d_yuv ? "yuv" : "rgb");
    printf("-%s ", d_range ? "ful" : "lim");
    printf(" %d -> %d", ival, oval);

    if( oval != ((d_yuv && !d_range) ? 188 : 200) )
        printf(" FAIL");
    printf("\n");
}

int main(int argc, char **argv)
{
    int i;
    for (i = 0; i < 3; i++) {
        a[i] = av_malloc(STRIDE_RGBA * H);
        b[i] = av_malloc(STRIDE_RGBA * H);
    }
    for (i = 0; i < 32; i++) {
        test(i);
        if (i % 16 == 15)
            printf("\n");
    }
}

thx

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I know you won't believe me, but the highest form of Human Excellence is
to question oneself and others. -- Socrates
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