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FFmpeg/libavcodec/kmvc.c
Andreas Rheinhardt 4243da4ff4 avcodec/codec_internal: Use union for FFCodec decode/encode callbacks 
This is possible, because every given FFCodec has to implement
exactly one of these. Doing so decreases sizeof(FFCodec) and
therefore decreases the size of the binary.
Notice that in case of position-independent code the decrease
is in .data.rel.ro, so that this translates to decreased
memory consumption.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2022-04-05 20:02:37 +02:00

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/*
* KMVC decoder
* Copyright (c) 2006 Konstantin Shishkov
*
* 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
*/
/**
* @file
* Karl Morton's Video Codec decoder
*/
#include <stdio.h>
#include <stdlib.h>
#include "avcodec.h"
#include "bytestream.h"
#include "codec_internal.h"
#include "decode.h"
#include "internal.h"
#include "libavutil/common.h"
#define KMVC_KEYFRAME 0x80
#define KMVC_PALETTE 0x40
#define KMVC_METHOD 0x0F
#define MAX_PALSIZE 256
/*
* Decoder context
*/
typedef struct KmvcContext {
AVCodecContext *avctx;
GetByteContext g;
uint8_t *cur, *prev;
int setpal;
int palsize;
uint32_t pal[MAX_PALSIZE];
uint8_t frm0[320 * 200], frm1[320 * 200];
} KmvcContext;
typedef struct BitBuf {
int bits;
int bitbuf;
} BitBuf;
#define BLK(data, x, y) data[av_clip((x) + (y) * 320, 0, 320 * 200 -1)]
#define kmvc_init_getbits(bb, g) bb.bits = 7; bb.bitbuf = bytestream2_get_byte(g);
#define kmvc_getbit(bb, g, res) {\
res = 0; \
if (bb.bitbuf & (1 << bb.bits)) res = 1; \
bb.bits--; \
if(bb.bits == -1) { \
bb.bitbuf = bytestream2_get_byte(g); \
bb.bits = 7; \
} \
}
static int kmvc_decode_intra_8x8(KmvcContext * ctx, int w, int h)
{
BitBuf bb;
int res, val;
int i, j;
int bx, by;
int l0x, l1x, l0y, l1y;
int mx, my;
kmvc_init_getbits(bb, &ctx->g);
for (by = 0; by < h; by += 8)
for (bx = 0; bx < w; bx += 8) {
if (!bytestream2_get_bytes_left(&ctx->g)) {
av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
return AVERROR_INVALIDDATA;
}
kmvc_getbit(bb, &ctx->g, res);
if (!res) { // fill whole 8x8 block
val = bytestream2_get_byte(&ctx->g);
for (i = 0; i < 64; i++)
BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val;
} else { // handle four 4x4 subblocks
for (i = 0; i < 4; i++) {
l0x = bx + (i & 1) * 4;
l0y = by + (i & 2) * 2;
kmvc_getbit(bb, &ctx->g, res);
if (!res) {
kmvc_getbit(bb, &ctx->g, res);
if (!res) { // fill whole 4x4 block
val = bytestream2_get_byte(&ctx->g);
for (j = 0; j < 16; j++)
BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val;
} else { // copy block from already decoded place
val = bytestream2_get_byte(&ctx->g);
mx = val & 0xF;
my = val >> 4;
if ((l0x-mx) + 320*(l0y-my) < 0 || (l0x-mx) + 320*(l0y-my) > 320*197 - 4) {
av_log(ctx->avctx, AV_LOG_ERROR, "Invalid MV\n");
return AVERROR_INVALIDDATA;
}
for (j = 0; j < 16; j++)
BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) =
BLK(ctx->cur, l0x + (j & 3) - mx, l0y + (j >> 2) - my);
}
} else { // descend to 2x2 sub-sub-blocks
for (j = 0; j < 4; j++) {
l1x = l0x + (j & 1) * 2;
l1y = l0y + (j & 2);
kmvc_getbit(bb, &ctx->g, res);
if (!res) {
kmvc_getbit(bb, &ctx->g, res);
if (!res) { // fill whole 2x2 block
val = bytestream2_get_byte(&ctx->g);
BLK(ctx->cur, l1x, l1y) = val;
BLK(ctx->cur, l1x + 1, l1y) = val;
BLK(ctx->cur, l1x, l1y + 1) = val;
BLK(ctx->cur, l1x + 1, l1y + 1) = val;
} else { // copy block from already decoded place
val = bytestream2_get_byte(&ctx->g);
mx = val & 0xF;
my = val >> 4;
if ((l1x-mx) + 320*(l1y-my) < 0 || (l1x-mx) + 320*(l1y-my) > 320*199 - 2) {
av_log(ctx->avctx, AV_LOG_ERROR, "Invalid MV\n");
return AVERROR_INVALIDDATA;
}
BLK(ctx->cur, l1x, l1y) = BLK(ctx->cur, l1x - mx, l1y - my);
BLK(ctx->cur, l1x + 1, l1y) =
BLK(ctx->cur, l1x + 1 - mx, l1y - my);
BLK(ctx->cur, l1x, l1y + 1) =
BLK(ctx->cur, l1x - mx, l1y + 1 - my);
BLK(ctx->cur, l1x + 1, l1y + 1) =
BLK(ctx->cur, l1x + 1 - mx, l1y + 1 - my);
}
} else { // read values for block
BLK(ctx->cur, l1x, l1y) = bytestream2_get_byte(&ctx->g);
BLK(ctx->cur, l1x + 1, l1y) = bytestream2_get_byte(&ctx->g);
BLK(ctx->cur, l1x, l1y + 1) = bytestream2_get_byte(&ctx->g);
BLK(ctx->cur, l1x + 1, l1y + 1) = bytestream2_get_byte(&ctx->g);
}
}
}
}
}
}
return 0;
}
static int kmvc_decode_inter_8x8(KmvcContext * ctx, int w, int h)
{
BitBuf bb;
int res, val;
int i, j;
int bx, by;
int l0x, l1x, l0y, l1y;
int mx, my;
kmvc_init_getbits(bb, &ctx->g);
for (by = 0; by < h; by += 8)
for (bx = 0; bx < w; bx += 8) {
kmvc_getbit(bb, &ctx->g, res);
if (!res) {
kmvc_getbit(bb, &ctx->g, res);
if (!res) { // fill whole 8x8 block
if (!bytestream2_get_bytes_left(&ctx->g)) {
av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
return AVERROR_INVALIDDATA;
}
val = bytestream2_get_byte(&ctx->g);
for (i = 0; i < 64; i++)
BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val;
} else { // copy block from previous frame
for (i = 0; i < 64; i++)
BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) =
BLK(ctx->prev, bx + (i & 0x7), by + (i >> 3));
}
} else { // handle four 4x4 subblocks
if (!bytestream2_get_bytes_left(&ctx->g)) {
av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
return AVERROR_INVALIDDATA;
}
for (i = 0; i < 4; i++) {
l0x = bx + (i & 1) * 4;
l0y = by + (i & 2) * 2;
kmvc_getbit(bb, &ctx->g, res);
if (!res) {
kmvc_getbit(bb, &ctx->g, res);
if (!res) { // fill whole 4x4 block
val = bytestream2_get_byte(&ctx->g);
for (j = 0; j < 16; j++)
BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val;
} else { // copy block
val = bytestream2_get_byte(&ctx->g);
mx = (val & 0xF) - 8;
my = (val >> 4) - 8;
if ((l0x+mx) + 320*(l0y+my) < 0 || (l0x+mx) + 320*(l0y+my) > 320*197 - 4) {
av_log(ctx->avctx, AV_LOG_ERROR, "Invalid MV\n");
return AVERROR_INVALIDDATA;
}
for (j = 0; j < 16; j++)
BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) =
BLK(ctx->prev, l0x + (j & 3) + mx, l0y + (j >> 2) + my);
}
} else { // descend to 2x2 sub-sub-blocks
for (j = 0; j < 4; j++) {
l1x = l0x + (j & 1) * 2;
l1y = l0y + (j & 2);
kmvc_getbit(bb, &ctx->g, res);
if (!res) {
kmvc_getbit(bb, &ctx->g, res);
if (!res) { // fill whole 2x2 block
val = bytestream2_get_byte(&ctx->g);
BLK(ctx->cur, l1x, l1y) = val;
BLK(ctx->cur, l1x + 1, l1y) = val;
BLK(ctx->cur, l1x, l1y + 1) = val;
BLK(ctx->cur, l1x + 1, l1y + 1) = val;
} else { // copy block
val = bytestream2_get_byte(&ctx->g);
mx = (val & 0xF) - 8;
my = (val >> 4) - 8;
if ((l1x+mx) + 320*(l1y+my) < 0 || (l1x+mx) + 320*(l1y+my) > 320*199 - 2) {
av_log(ctx->avctx, AV_LOG_ERROR, "Invalid MV\n");
return AVERROR_INVALIDDATA;
}
BLK(ctx->cur, l1x, l1y) = BLK(ctx->prev, l1x + mx, l1y + my);
BLK(ctx->cur, l1x + 1, l1y) =
BLK(ctx->prev, l1x + 1 + mx, l1y + my);
BLK(ctx->cur, l1x, l1y + 1) =
BLK(ctx->prev, l1x + mx, l1y + 1 + my);
BLK(ctx->cur, l1x + 1, l1y + 1) =
BLK(ctx->prev, l1x + 1 + mx, l1y + 1 + my);
}
} else { // read values for block
BLK(ctx->cur, l1x, l1y) = bytestream2_get_byte(&ctx->g);
BLK(ctx->cur, l1x + 1, l1y) = bytestream2_get_byte(&ctx->g);
BLK(ctx->cur, l1x, l1y + 1) = bytestream2_get_byte(&ctx->g);
BLK(ctx->cur, l1x + 1, l1y + 1) = bytestream2_get_byte(&ctx->g);
}
}
}
}
}
}
return 0;
}
static int decode_frame(AVCodecContext * avctx, AVFrame *frame,
int *got_frame, AVPacket *avpkt)
{
KmvcContext *const ctx = avctx->priv_data;
uint8_t *out, *src;
int i, ret;
int header;
int blocksize;
bytestream2_init(&ctx->g, avpkt->data, avpkt->size);
if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
return ret;
frame->palette_has_changed = ff_copy_palette(ctx->pal, avpkt, avctx);
header = bytestream2_get_byte(&ctx->g);
/* blocksize 127 is really palette change event */
if (bytestream2_peek_byte(&ctx->g) == 127) {
bytestream2_skip(&ctx->g, 3);
for (i = 0; i < 127; i++) {
ctx->pal[i + (header & 0x81)] = 0xFFU << 24 | bytestream2_get_be24(&ctx->g);
bytestream2_skip(&ctx->g, 1);
}
bytestream2_seek(&ctx->g, -127 * 4 - 3, SEEK_CUR);
}
if (header & KMVC_KEYFRAME) {
frame->key_frame = 1;
frame->pict_type = AV_PICTURE_TYPE_I;
} else {
frame->key_frame = 0;
frame->pict_type = AV_PICTURE_TYPE_P;
}
if (header & KMVC_PALETTE) {
frame->palette_has_changed = 1;
// palette starts from index 1 and has 127 entries
for (i = 1; i <= ctx->palsize; i++) {
ctx->pal[i] = 0xFFU << 24 | bytestream2_get_be24(&ctx->g);
}
}
if (ctx->setpal) {
ctx->setpal = 0;
frame->palette_has_changed = 1;
}
/* make the palette available on the way out */
memcpy(frame->data[1], ctx->pal, 1024);
blocksize = bytestream2_get_byte(&ctx->g);
if (blocksize != 8 && blocksize != 127) {
av_log(avctx, AV_LOG_ERROR, "Block size = %i\n", blocksize);
return AVERROR_INVALIDDATA;
}
memset(ctx->cur, 0, 320 * 200);
switch (header & KMVC_METHOD) {
case 0:
case 1: // used in palette changed event
memcpy(ctx->cur, ctx->prev, 320 * 200);
break;
case 3:
kmvc_decode_intra_8x8(ctx, avctx->width, avctx->height);
break;
case 4:
kmvc_decode_inter_8x8(ctx, avctx->width, avctx->height);
break;
default:
av_log(avctx, AV_LOG_ERROR, "Unknown compression method %i\n", header & KMVC_METHOD);
return AVERROR_INVALIDDATA;
}
out = frame->data[0];
src = ctx->cur;
for (i = 0; i < avctx->height; i++) {
memcpy(out, src, avctx->width);
src += 320;
out += frame->linesize[0];
}
/* flip buffers */
FFSWAP(uint8_t *, ctx->cur, ctx->prev);
*got_frame = 1;
/* always report that the buffer was completely consumed */
return avpkt->size;
}
/*
* Init kmvc decoder
*/
static av_cold int decode_init(AVCodecContext * avctx)
{
KmvcContext *const c = avctx->priv_data;
int i;
c->avctx = avctx;
if (avctx->width > 320 || avctx->height > 200) {
av_log(avctx, AV_LOG_ERROR, "KMVC supports frames <= 320x200\n");
return AVERROR(EINVAL);
}
c->cur = c->frm0;
c->prev = c->frm1;
for (i = 0; i < 256; i++) {
c->pal[i] = 0xFFU << 24 | i * 0x10101;
}
if (avctx->extradata_size < 12) {
av_log(avctx, AV_LOG_WARNING,
"Extradata missing, decoding may not work properly...\n");
c->palsize = 127;
} else {
c->palsize = AV_RL16(avctx->extradata + 10);
if (c->palsize >= (unsigned)MAX_PALSIZE) {
c->palsize = 127;
av_log(avctx, AV_LOG_ERROR, "KMVC palette too large\n");
return AVERROR_INVALIDDATA;
}
}
if (avctx->extradata_size == 1036) { // palette in extradata
uint8_t *src = avctx->extradata + 12;
for (i = 0; i < 256; i++) {
c->pal[i] = AV_RL32(src);
src += 4;
}
c->setpal = 1;
}
avctx->pix_fmt = AV_PIX_FMT_PAL8;
return 0;
}
const FFCodec ff_kmvc_decoder = {
.p.name = "kmvc",
.p.long_name = NULL_IF_CONFIG_SMALL("Karl Morton's video codec"),
.p.type = AVMEDIA_TYPE_VIDEO,
.p.id = AV_CODEC_ID_KMVC,
.priv_data_size = sizeof(KmvcContext),
.init = decode_init,
FF_CODEC_DECODE_CB(decode_frame),
.p.capabilities = AV_CODEC_CAP_DR1,
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
};
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