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/*
* FFv1 codec
*
* Copyright (c) 2024 Lynne <dev@lynne.ee>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
ivec2 get_diff(ivec2 pos, ivec2 off, int p, int comp, int sw, int bits)
{
const ivec2 yoff_border1 = off.x == 0 ? ivec2(1, -1) : ivec2(0, 0);
const ivec2 yoff_border2 = off.x == 1 ? ivec2(1, -1) : ivec2(0, 0);
TYPE top2 = TYPE(0);
if (off.y > 1)
top2 = TYPE(imageLoad(src[p], pos + ivec2(0, -2))[comp]);
VTYPE3 top = VTYPE3(TYPE(0),
TYPE(0),
TYPE(0));
if (off.y > 0 && off != ivec2(0, 1))
top[0] = TYPE(imageLoad(src[p], pos + ivec2(-1, -1) + yoff_border1)[comp]);
if (off.y > 0) {
top[1] = TYPE(imageLoad(src[p], pos + ivec2(0, -1))[comp]);
top[2] = TYPE(imageLoad(src[p], pos + ivec2(min(1, sw - off.x - 1), -1))[comp]);
}
VTYPE3 cur = VTYPE3(TYPE(0),
TYPE(0),
imageLoad(src[p], pos)[comp]);
if (off.x > 0 && off != ivec2(1, 0))
cur[0] = TYPE(imageLoad(src[p], pos + ivec2(-2, 0) + yoff_border2)[comp]);
if (off != ivec2(0, 0))
cur[1] = TYPE(imageLoad(src[p], pos + ivec2(-1, 0) + yoff_border1)[comp]);
/* context, diff */
ivec2 d = ivec2(get_context(VTYPE2(cur), top, top2, context_model),
cur[2] - predict(cur[1], VTYPE2(top)));
if (d[0] < 0)
d = -d;
d[1] = fold(d[1], bits);
return d;
}
void finalize_slice(inout SliceContext sc, const uint slice_idx)
{
#ifdef GOLOMB
uint32_t enc_len = sc.hdr_len + flush_put_bits(sc.pb);
#else
uint32_t enc_len = rac_terminate(sc.c);
#endif
u8buf bs = u8buf(sc.c.bytestream_start);
/* Append slice length */
u8vec4 enc_len_p = unpack8(enc_len);
bs[enc_len + 0].v = enc_len_p.z;
bs[enc_len + 1].v = enc_len_p.y;
bs[enc_len + 2].v = enc_len_p.x;
enc_len += 3;
/* Calculate and write CRC */
if (ec != 0) {
bs[enc_len].v = uint8_t(0);
enc_len++;
uint32_t crc = crcref;
for (int i = 0; i < enc_len; i++)
crc = crc_ieee[(crc & 0xFF) ^ uint32_t(bs[i].v)] ^ (crc >> 8);
if (crcref != 0x00000000)
crc ^= 0x8CD88196;
u8vec4 crc_p = unpack8(crc);
bs[enc_len + 0].v = crc_p.x;
bs[enc_len + 1].v = crc_p.y;
bs[enc_len + 2].v = crc_p.z;
bs[enc_len + 3].v = crc_p.w;
enc_len += 4;
}
slice_results[slice_idx*2 + 0] = enc_len;
slice_results[slice_idx*2 + 1] = uint64_t(bs) - uint64_t(out_data);
}