[FFmpeg-devel] [PATCH] avcodec/ffv1: Support slice coding mode 1 with golomb rice
Lynne
dev at lynne.ee
Fri Oct 25 05:24:04 EEST 2024
On 25/10/2024 03:57, Michael Niedermayer wrote:
> Sponsored-by: Sovereign Tech Fund
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
> libavcodec/ffv1dec.c | 20 ++++++++++----------
> libavcodec/ffv1dec_template.c | 3 +++
> libavcodec/ffv1enc.c | 23 ++++++++++++-----------
> 3 files changed, 25 insertions(+), 21 deletions(-)
>
> diff --git a/libavcodec/ffv1dec.c b/libavcodec/ffv1dec.c
> index ac8cc8a31dc..de5abfe9b41 100644
> --- a/libavcodec/ffv1dec.c
> +++ b/libavcodec/ffv1dec.c
> @@ -120,9 +120,8 @@ 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 pixel_stride, int ac)
> {
> - const int ac = f->ac;
> int x, y;
> int16_t *sample[2];
> sample[0] = sc->sample_buffer + 3;
> @@ -273,6 +272,7 @@ static int decode_slice(AVCodecContext *c, void *arg)
> AVFrame * const p = f->picture.f;
> const int si = sc - f->slices;
> GetBitContext gb;
> + int ac = f->ac || sc->slice_coding_mode == 1;
>
> if (!(p->flags & AV_FRAME_FLAG_KEY) && f->last_picture.f)
> ff_progress_frame_await(&f->last_picture, si);
> @@ -305,7 +305,7 @@ static int decode_slice(AVCodecContext *c, void *arg)
> x = sc->slice_x;
> y = sc->slice_y;
>
> - if (f->ac == AC_GOLOMB_RICE) {
> + if (ac == AC_GOLOMB_RICE) {
> if (f->version == 3 && f->micro_version > 1 || f->version > 3)
> get_rac(&sc->c, (uint8_t[]) { 129 });
> sc->ac_byte_count = f->version > 2 || (!x && !y) ? sc->c.bytestream - sc->c.bytestream_start - 1 : 0;
> @@ -320,17 +320,17 @@ static int decode_slice(AVCodecContext *c, void *arg)
> const int chroma_height = AV_CEIL_RSHIFT(height, f->chroma_v_shift);
> 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);
> + decode_plane(f, sc, &gb, p->data[0] + ps*x + y*p->linesize[0], width, height, p->linesize[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);
> - decode_plane(f, sc, &gb, p->data[2] + ps*cx+cy*p->linesize[2], chroma_width, chroma_height, p->linesize[2], 1, 1);
> + 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);
> }
> 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);
> + 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);
> } 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);
> - decode_plane(f, sc, &gb, p->data[0] + ps*x + y*p->linesize[0] + 1, width, height, p->linesize[0], 1, 2);
> + 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);
> } 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],
> @@ -344,7 +344,7 @@ static int decode_slice(AVCodecContext *c, void *arg)
> p->data[3] + ps * x + y * p->linesize[3] };
> decode_rgb_frame(f, sc, &gb, planes, width, height, p->linesize);
> }
> - if (f->ac != AC_GOLOMB_RICE && f->version > 2) {
> + if (ac != AC_GOLOMB_RICE && f->version > 2) {
> int v;
> get_rac(&sc->c, (uint8_t[]) { 129 });
> v = sc->c.bytestream_end - sc->c.bytestream - 2 - 5*!!f->ec;
> diff --git a/libavcodec/ffv1dec_template.c b/libavcodec/ffv1dec_template.c
> index 2da6bd935dc..e983d1ba648 100644
> --- a/libavcodec/ffv1dec_template.c
> +++ b/libavcodec/ffv1dec_template.c
> @@ -143,6 +143,9 @@ static int RENAME(decode_rgb_frame)(FFV1Context *f, FFV1SliceContext *sc,
> int transparency = f->transparency;
> int ac = f->ac;
>
> + if (sc->slice_coding_mode == 1)
> + ac = 1;
> +
> for (x = 0; x < 4; x++) {
> sample[x][0] = RENAME(sc->sample_buffer) + x * 2 * (w + 6) + 3;
> sample[x][1] = RENAME(sc->sample_buffer) + (x * 2 + 1) * (w + 6) + 3;
> diff --git a/libavcodec/ffv1enc.c b/libavcodec/ffv1enc.c
> index a32059886c0..547fb598d6d 100644
> --- a/libavcodec/ffv1enc.c
> +++ b/libavcodec/ffv1enc.c
> @@ -271,10 +271,9 @@ 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 stride, int plane_index, int pixel_stride, int ac)
> {
> int x, y, i, ret;
> - const int ac = f->ac;
> const int pass1 = !!(f->avctx->flags & AV_CODEC_FLAG_PASS1);
> const int ring_size = f->context_model ? 3 : 2;
> int16_t *sample[3];
> @@ -1068,6 +1067,7 @@ static int encode_slice(AVCodecContext *c, void *arg)
> p->data[1] ? p->data[1] + ps*x + y*p->linesize[1] : NULL,
> p->data[2] ? p->data[2] + ps*x + y*p->linesize[2] : NULL,
> p->data[3] ? p->data[3] + ps*x + y*p->linesize[3] : NULL};
> + int ac = f->ac;
>
> sc->slice_coding_mode = 0;
> if (f->version > 3 && f->colorspace == 1) {
> @@ -1083,7 +1083,7 @@ retry:
> if (f->version > 2) {
> encode_slice_header(f, sc);
> }
> - if (f->ac == AC_GOLOMB_RICE) {
> + if (ac == AC_GOLOMB_RICE) {
> sc->ac_byte_count = f->version > 2 || (!x && !y) ? ff_rac_terminate(&sc->c, f->version > 2) : 0;
> init_put_bits(&sc->pb,
> sc->c.bytestream_start + sc->ac_byte_count,
> @@ -1096,24 +1096,24 @@ 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);
> + ret = encode_plane(f, sc, p->data[0] + ps*x + y*p->linesize[0], width, height, p->linesize[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);
> - ret |= encode_plane(f, sc, p->data[2] + ps*cx+cy*p->linesize[2], chroma_width, chroma_height, p->linesize[2], 1, 1);
> + 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);
> }
> if (f->transparency)
> - ret |= encode_plane(f, sc, p->data[3] + ps*x + y*p->linesize[3], width, height, p->linesize[3], 2, 1);
> + ret |= encode_plane(f, sc, p->data[3] + ps*x + y*p->linesize[3], width, height, p->linesize[3], 2, 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);
> - ret |= encode_plane(f, sc, p->data[0] + 1 + ps*x + y*p->linesize[0], width, height, p->linesize[0], 1, 2);
> + 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);
> } else if (f->use32bit) {
> ret = encode_rgb_frame32(f, sc, planes, width, height, p->linesize);
> } else {
> ret = encode_rgb_frame(f, sc, planes, width, height, p->linesize);
> }
>
> - if (f->ac != AC_GOLOMB_RICE) {
> + if (ac != AC_GOLOMB_RICE) {
> sc->ac_byte_count = ff_rac_terminate(&sc->c, 1);
> } else {
> flush_put_bits(&sc->pb); // FIXME: nicer padding
> @@ -1122,11 +1122,12 @@ retry:
>
> if (ret < 0) {
> av_assert0(sc->slice_coding_mode == 0);
> - if (f->version < 4 || !f->ac) {
> + if (f->version < 4) {
> av_log(c, AV_LOG_ERROR, "Buffer too small\n");
> return ret;
> }
> av_log(c, AV_LOG_DEBUG, "Coding slice as PCM\n");
> + ac = 1;
> sc->slice_coding_mode = 1;
> sc->c = c_bak;
> goto retry;
Is there a reason to support this with Golomb? Being a fallback-only
mode for range coding, I don't think there's much point in supporting
Golomb coding for it.
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