[FFmpeg-devel] [PATCH] ffv1: implement remap for encode/decode_plane()

James Almer jamrial at gmail.com
Tue Mar 11 21:06:58 EET 2025



On 3/11/2025 11:13 AM, James Almer wrote:
> On 3/10/2025 9:59 PM, Michael Niedermayer wrote:
>> On Mon, Mar 10, 2025 at 06:48:29PM +0100, Lynne wrote:
>>> On 10/03/2025 01:45, Michael Niedermayer wrote:
>>>> Sponsored-by: Sovereign Tech Fund
>>>> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
>>>> ---
>>>>    libavcodec/ffv1dec.c | 20 ++++++++-----
>>>>    libavcodec/ffv1enc.c | 67 +++++++++++++++++++++++++++++++++++++ 
>>>> +------
>>>>    2 files changed, 71 insertions(+), 16 deletions(-)
>>>>
>>>> diff --git a/libavcodec/ffv1dec.c b/libavcodec/ffv1dec.c
>>>> index 9738e4e9c9f..72c93fcf0cd 100644
>>>> --- a/libavcodec/ffv1dec.c
>>>> +++ b/libavcodec/ffv1dec.c
>>>> @@ -92,7 +92,7 @@ static int is_input_end(RangeCoder *c, 
>>>> GetBitContext *gb, int ac)
>>>>    static int decode_plane(FFV1Context *f, FFV1SliceContext *sc,
>>>>                            GetBitContext *gb,
>>>>                            uint8_t *src, int w, int h, int stride, 
>>>> int plane_index,
>>>> -                        int pixel_stride, int ac)
>>>> +                        int remap_index, int pixel_stride, int ac)
>>>>    {
>>>>        int x, y;
>>>>        int16_t *sample[2];
>>>> @@ -116,12 +116,18 @@ static int decode_plane(FFV1Context *f, 
>>>> FFV1SliceContext *sc,
>>>>                int ret = decode_line(f, sc, gb, w, sample, 
>>>> plane_index, 8, ac);
>>>>                if (ret < 0)
>>>>                    return ret;
>>>> +            if (sc->remap)
>>>> +                for (x = 0; x < w; x++)
>>>> +                    sample[1][x] = sc->fltmap[remap_index] 
>>>> [sample[1][x]];
>>>>                for (x = 0; x < w; x++)
>>>>                    src[x*pixel_stride + stride * y] = sample[1][x];
>>>>            } else {
>>>>                int ret = decode_line(f, sc, gb, w, sample, 
>>>> plane_index, f->avctx->bits_per_raw_sample, ac);
>>>>                if (ret < 0)
>>>>                    return ret;
>>>> +            if (sc->remap)
>>>> +                for (x = 0; x < w; x++)
>>>> +                    sample[1][x] = sc->fltmap[remap_index] 
>>>> [sample[1][x]];
>>>>                if (f->packed_at_lsb) {
>>>>                    for (x = 0; x < w; x++) {
>>>>                        ((uint16_t*)(src + stride*y))[x*pixel_stride] 
>>>> = sample[1][x];
>>>> @@ -347,17 +353,17 @@ static int decode_slice(AVCodecContext *c, 
>>>> void *arg)
>>>>        if (f->colorspace == 0 && (f->chroma_planes || !f- 
>>>> >transparency)) {
>>>>            const int cx            = x >> f->chroma_h_shift;
>>>>            const int cy            = y >> f->chroma_v_shift;
>>>> -        decode_plane(f, sc, &gb, p->data[0] + ps*x + y*p- 
>>>> >linesize[0], width, height, p->linesize[0], 0, 1, ac);
>>>> +        decode_plane(f, sc, &gb, p->data[0] + ps*x + y*p- 
>>>> >linesize[0], width, height, p->linesize[0], 0, 0, 1, ac);
>>>>            if (f->chroma_planes) {
>>>> -            decode_plane(f, sc, &gb, p->data[1] + ps*cx+cy*p- 
>>>> >linesize[1], chroma_width, chroma_height, p->linesize[1], 1, 1, ac);
>>>> -            decode_plane(f, sc, &gb, p->data[2] + ps*cx+cy*p- 
>>>> >linesize[2], chroma_width, chroma_height, p->linesize[2], 1, 1, ac);
>>>> +            decode_plane(f, sc, &gb, p->data[1] + ps*cx+cy*p- 
>>>> >linesize[1], chroma_width, chroma_height, p->linesize[1], 1, 1, 1, 
>>>> ac);
>>>> +            decode_plane(f, sc, &gb, p->data[2] + ps*cx+cy*p- 
>>>> >linesize[2], chroma_width, chroma_height, p->linesize[2], 1, 2, 1, 
>>>> ac);
>>>>            }
>>>>            if (f->transparency)
>>>> -            decode_plane(f, sc, &gb, p->data[3] + ps*x + y*p- 
>>>> >linesize[3], width, height, p->linesize[3], (f->version >= 4 && !f- 
>>>> >chroma_planes) ? 1 : 2, 1, ac);
>>>> +            decode_plane(f, sc, &gb, p->data[3] + ps*x + y*p- 
>>>> >linesize[3], width, height, p->linesize[3], (f->version >= 4 && !f- 
>>>> >chroma_planes) ? 1 : 2, 2, 1, ac);
>>>>        } else if (f->colorspace == 0) {
>>>> -         decode_plane(f, sc, &gb, p->data[0] + ps*x + y*p- 
>>>> >linesize[0]    , width, height, p->linesize[0], 0, 2, ac);
>>>> -         decode_plane(f, sc, &gb, p->data[0] + ps*x + y*p- 
>>>> >linesize[0] + 1, width, height, p->linesize[0], 1, 2, ac);
>>>> +         decode_plane(f, sc, &gb, p->data[0] + ps*x + y*p- 
>>>> >linesize[0]    , width, height, p->linesize[0], 0, 0, 2, ac);
>>>> +         decode_plane(f, sc, &gb, p->data[0] + ps*x + y*p- 
>>>> >linesize[0] + 1, width, height, p->linesize[0], 1, 1, 2, ac);
>>>>        } else if (f->use32bit) {
>>>>            uint8_t *planes[4] = { p->data[0] + ps * x + y * p- 
>>>> >linesize[0],
>>>>                                   p->data[1] + ps * x + y * p- 
>>>> >linesize[1],
>>>> diff --git a/libavcodec/ffv1enc.c b/libavcodec/ffv1enc.c
>>>> index f3041219b71..4c55c01263b 100644
>>>> --- a/libavcodec/ffv1enc.c
>>>> +++ b/libavcodec/ffv1enc.c
>>>> @@ -272,7 +272,7 @@ static inline void put_vlc_symbol(PutBitContext 
>>>> *pb, VlcState *const state,
>>>>    static int encode_plane(FFV1Context *f, FFV1SliceContext *sc,
>>>>                            const uint8_t *src, int w, int h,
>>>> -                         int stride, int plane_index, int 
>>>> pixel_stride, int ac)
>>>> +                        int stride, int plane_index, int 
>>>> remap_index, int pixel_stride, int ac)
>>>>    {
>>>>        int x, y, i, ret;
>>>>        const int pass1 = !!(f->avctx->flags & AV_CODEC_FLAG_PASS1);
>>>> @@ -288,9 +288,14 @@ static int encode_plane(FFV1Context *f, 
>>>> FFV1SliceContext *sc,
>>>>            sample[0][-1]= sample[1][0  ];
>>>>            sample[1][ w]= sample[1][w-1];
>>>> +
>>>>            if (f->bits_per_raw_sample <= 8) {
>>>>                for (x = 0; x < w; x++)
>>>>                    sample[0][x] = src[x * pixel_stride + stride * y];
>>>> +            if (sc->remap)
>>>> +                for (x = 0; x < w; x++)
>>>> +                    sample[0][x] = sc->fltmap[remap_index] 
>>>> [ sample[0][x] ];
>>>> +
>>>>                if((ret = encode_line(f, sc, f->avctx, w, sample, 
>>>> plane_index, 8, ac, pass1)) < 0)
>>>>                    return ret;
>>>>            } else {
>>>> @@ -303,6 +308,10 @@ static int encode_plane(FFV1Context *f, 
>>>> FFV1SliceContext *sc,
>>>>                        sample[0][x] = ((uint16_t*)(src + stride*y)) 
>>>> [x] >> (16 - f->bits_per_raw_sample);
>>>>                    }
>>>>                }
>>>> +            if (sc->remap)
>>>> +                for (x = 0; x < w; x++)
>>>> +                    sample[0][x] = sc->fltmap[remap_index] 
>>>> [ sample[0][x] ];
>>>> +
>>>>                if((ret = encode_line(f, sc, f->avctx, w, sample, 
>>>> plane_index, f->bits_per_raw_sample, ac, pass1)) < 0)
>>>>                    return ret;
>>>>            }
>>>> @@ -310,6 +319,30 @@ static int encode_plane(FFV1Context *f, 
>>>> FFV1SliceContext *sc,
>>>>        return 0;
>>>>    }
>>>> +static void load_plane(FFV1Context *f, FFV1SliceContext *sc,
>>>> +                      const uint8_t *src, int w, int h,
>>>> +                      int stride, int remap_index, int pixel_stride)
>>>> +{
>>>> +    int x, y;
>>>> +
>>>> +    memset(sc->fltmap[remap_index], 0, sizeof(sc- 
>>>> >fltmap[remap_index]));
>>>> +
>>>> +    for (y = 0; y < h; y++) {
>>>> +        if (f->bits_per_raw_sample <= 8) {
>>>> +            for (x = 0; x < w; x++)
>>>> +                sc->fltmap[remap_index][ src[x * pixel_stride + 
>>>> stride * y] ] = 1;
>>>> +        } else {
>>>> +            if (f->packed_at_lsb) {
>>>> +                for (x = 0; x < w; x++)
>>>> +                    sc->fltmap[remap_index][ ((uint16_t*)(src + 
>>>> stride*y))[x] ] = 1;
>>>> +            } else {
>>>> +                for (x = 0; x < w; x++)
>>>> +                    sc->fltmap[remap_index][ ((uint16_t*)(src + 
>>>> stride*y))[x] >> (16 - f->bits_per_raw_sample) ] = 1;
>>>> +            }
>>>> +        }
>>>> +    }
>>>> +}
>>>> +
>>>>    static void write_quant_table(RangeCoder *c, int16_t *quant_table)
>>>>    {
>>>>        int last = 0;
>>>> @@ -1178,8 +1211,24 @@ retry:
>>>>        }
>>>>        if (sc->remap) {
>>>> -        if (f->colorspace == 0) {
>>>> -            av_assert0(0);
>>>> +        if (f->colorspace == 0 && c->pix_fmt != AV_PIX_FMT_YA8) {
>>>> +            const int cx            = x >> f->chroma_h_shift;
>>>> +            const int cy            = y >> f->chroma_v_shift;
>>>> +
>>>> +            //TODO decide on the order for the encoded remaps and 
>>>> loads. with golomb rice it
>>>> +            // easier to have all range coded ones together, 
>>>> otherwise it may be nicer to handle each plane as a whole?
>>>> +
>>>> +            load_plane(f, sc, p->data[0] + ps*x + y*p->linesize[0], 
>>>> width, height, p->linesize[0], 0, 1);
>>>> +
>>>> +            if (f->chroma_planes) {
>>>> +                load_plane(f, sc, p->data[1] + ps*cx+cy*p- 
>>>> >linesize[1], chroma_width, chroma_height, p->linesize[1], 1, 1);
>>>> +                load_plane(f, sc, p->data[2] + ps*cx+cy*p- 
>>>> >linesize[2], chroma_width, chroma_height, p->linesize[2], 2, 1);
>>>> +            }
>>>> +            if (f->transparency)
>>>> +                load_plane(f, sc, p->data[3] + ps*x + y*p- 
>>>> >linesize[3], width, height, p->linesize[3], 3, 1);
>>>> +        } else if (c->pix_fmt == AV_PIX_FMT_YA8) {
>>>> +            load_plane(f, sc, p->data[0] +     ps*x + y*p- 
>>>> >linesize[0], width, height, p->linesize[0], 0, 2);
>>>> +            load_plane(f, sc, p->data[0] + 1 + ps*x + y*p- 
>>>> >linesize[0], width, height, p->linesize[0], 1, 2);
>>>>            } else if (f->use32bit) {
>>>>                load_rgb_frame32(f, sc, planes, width, height, p- 
>>>> >linesize);
>>>>            } else
>>>> @@ -1206,17 +1255,17 @@ retry:
>>>>            const int cx            = x >> f->chroma_h_shift;
>>>>            const int cy            = y >> f->chroma_v_shift;
>>>> -        ret = encode_plane(f, sc, p->data[0] + ps*x + y*p- 
>>>> >linesize[0], width, height, p->linesize[0], 0, 1, ac);
>>>> +        ret = encode_plane(f, sc, p->data[0] + ps*x + y*p- 
>>>> >linesize[0], width, height, p->linesize[0], 0, 0, 1, ac);
>>>>            if (f->chroma_planes) {
>>>> -            ret |= encode_plane(f, sc, p->data[1] + ps*cx+cy*p- 
>>>> >linesize[1], chroma_width, chroma_height, p->linesize[1], 1, 1, ac);
>>>> -            ret |= encode_plane(f, sc, p->data[2] + ps*cx+cy*p- 
>>>> >linesize[2], chroma_width, chroma_height, p->linesize[2], 1, 1, ac);
>>>> +            ret |= encode_plane(f, sc, p->data[1] + ps*cx+cy*p- 
>>>> >linesize[1], chroma_width, chroma_height, p->linesize[1], 1, 1, 1, 
>>>> ac);
>>>> +            ret |= encode_plane(f, sc, p->data[2] + ps*cx+cy*p- 
>>>> >linesize[2], chroma_width, chroma_height, p->linesize[2], 1, 2, 1, 
>>>> ac);
>>>>            }
>>>>            if (f->transparency)
>>>> -            ret |= encode_plane(f, sc, p->data[3] + ps*x + y*p- 
>>>> >linesize[3], width, height, p->linesize[3], 2, 1, ac);
>>>> +            ret |= encode_plane(f, sc, p->data[3] + ps*x + y*p- 
>>>> >linesize[3], width, height, p->linesize[3], 2, 3, 1, ac);
>>>>        } else if (c->pix_fmt == AV_PIX_FMT_YA8) {
>>>> -        ret  = encode_plane(f, sc, p->data[0] +     ps*x + y*p- 
>>>> >linesize[0], width, height, p->linesize[0], 0, 2, ac);
>>>> -        ret |= encode_plane(f, sc, p->data[0] + 1 + ps*x + y*p- 
>>>> >linesize[0], width, height, p->linesize[0], 1, 2, ac);
>>>> +        ret  = encode_plane(f, sc, p->data[0] +     ps*x + y*p- 
>>>> >linesize[0], width, height, p->linesize[0], 0, 0, 2, ac);
>>>> +        ret |= encode_plane(f, sc, p->data[0] + 1 + ps*x + y*p- 
>>>> >linesize[0], width, height, p->linesize[0], 1, 1, 2, ac);
>>>>        } else if (f->use32bit) {
>>>>            ret = encode_rgb_frame32(f, sc, planes, width, height, p- 
>>>> >linesize, ac);
>>>>        } else {
>>>
>>> Doesn't apply properly.
>>> What does it even do? Does the current git master not already do this?
>>
>> master implements remap for encode_rgb_frame*
>> This implements it for the other cases.
>> Most of this is untested though, i have no YUV planar float16 material
> There is one very tiny exr sample that's YA float16, the one from fate- 
> exr-ya-scanline-zip-half-12x8. Not sure how useful can it be considering 
> it's so small and has no chroma planes.

There's also 
https://raw.githubusercontent.com/AcademySoftwareFoundation/openexr-images/main/LuminanceChroma/Garden.exr 
which is grayf16.

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