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FFmpeg/libavcodec/vb.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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/*
* Beam Software VB decoder
* Copyright (c) 2007 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
* VB Video decoder
*/
#include <stdio.h>
#include <stdlib.h>
#include "avcodec.h"
#include "bytestream.h"
#include "codec_internal.h"
#include "internal.h"
enum VBFlags {
VB_HAS_GMC = 0x01,
VB_HAS_AUDIO = 0x04,
VB_HAS_VIDEO = 0x08,
VB_HAS_PALETTE = 0x10,
VB_HAS_LENGTH = 0x20
};
typedef struct VBDecContext {
AVCodecContext *avctx;
uint8_t *frame, *prev_frame;
uint32_t pal[AVPALETTE_COUNT];
GetByteContext stream;
} VBDecContext;
static const uint16_t vb_patterns[64] = {
0x0660, 0xFF00, 0xCCCC, 0xF000, 0x8888, 0x000F, 0x1111, 0xFEC8,
0x8CEF, 0x137F, 0xF731, 0xC800, 0x008C, 0x0013, 0x3100, 0xCC00,
0x00CC, 0x0033, 0x3300, 0x0FF0, 0x6666, 0x00F0, 0x0F00, 0x2222,
0x4444, 0xF600, 0x8CC8, 0x006F, 0x1331, 0x318C, 0xC813, 0x33CC,
0x6600, 0x0CC0, 0x0066, 0x0330, 0xF900, 0xC88C, 0x009F, 0x3113,
0x6000, 0x0880, 0x0006, 0x0110, 0xCC88, 0xFC00, 0x00CF, 0x88CC,
0x003F, 0x1133, 0x3311, 0xF300, 0x6FF6, 0x0603, 0x08C6, 0x8C63,
0xC631, 0x6310, 0xC060, 0x0136, 0x136C, 0x36C8, 0x6C80, 0x324C
};
static void vb_decode_palette(VBDecContext *c, int data_size)
{
int start, size, i;
start = bytestream2_get_byte(&c->stream);
size = (bytestream2_get_byte(&c->stream) - 1) & 0xFF;
if (start + size > 255) {
av_log(c->avctx, AV_LOG_ERROR, "Palette change runs beyond entry 256\n");
return;
}
if (size*3+2 > data_size) {
av_log(c->avctx, AV_LOG_ERROR, "Palette data runs beyond chunk size\n");
return;
}
for (i = start; i <= start + size; i++)
c->pal[i] = 0xFFU << 24 | bytestream2_get_be24(&c->stream);
}
static inline int check_pixel(uint8_t *buf, uint8_t *start, uint8_t *end)
{
return buf >= start && buf < end;
}
static inline int check_line(uint8_t *buf, uint8_t *start, uint8_t *end)
{
return buf >= start && (buf + 4) <= end;
}
static int vb_decode_framedata(VBDecContext *c, int offset)
{
GetByteContext g;
uint8_t *prev, *cur;
int blk, blocks, t, blk2;
int blocktypes = 0;
int x, y, a, b;
int pattype, pattern;
const int width = c->avctx->width;
uint8_t *pstart = c->prev_frame;
uint8_t *pend = c->prev_frame + width*c->avctx->height;
g = c->stream;
prev = c->prev_frame + offset;
cur = c->frame;
blocks = (c->avctx->width >> 2) * (c->avctx->height >> 2);
blk2 = 0;
for (blk = 0; blk < blocks; blk++) {
if (!(blk & 3)) {
if (bytestream2_get_bytes_left(&g) < 1) {
av_log(c->avctx, AV_LOG_ERROR, "Insufficient data\n");
return AVERROR_INVALIDDATA;
}
blocktypes = bytestream2_get_byte(&g);
}
switch (blocktypes & 0xC0) {
case 0x00: //skip
for (y = 0; y < 4; y++)
if (check_line(prev + y*width, pstart, pend))
memcpy(cur + y*width, prev + y*width, 4);
else
memset(cur + y*width, 0, 4);
break;
case 0x40:
t = bytestream2_get_byte(&g);
if (!t) { //raw block
if (bytestream2_get_bytes_left(&g) < 16) {
av_log(c->avctx, AV_LOG_ERROR, "Insufficient data\n");
return AVERROR_INVALIDDATA;
}
for (y = 0; y < 4; y++)
bytestream2_get_buffer(&g, cur + y * width, 4);
} else { // motion compensation
x = ((t & 0xF)^8) - 8;
y = ((t >> 4) ^8) - 8;
t = x + y*width;
for (y = 0; y < 4; y++)
if (check_line(prev + t + y*width, pstart, pend))
memcpy(cur + y*width, prev + t + y*width, 4);
else
memset(cur + y*width, 0, 4);
}
break;
case 0x80: // fill
t = bytestream2_get_byte(&g);
for (y = 0; y < 4; y++)
memset(cur + y*width, t, 4);
break;
case 0xC0: // pattern fill
t = bytestream2_get_byte(&g);
pattype = t >> 6;
pattern = vb_patterns[t & 0x3F];
switch (pattype) {
case 0:
a = bytestream2_get_byte(&g);
b = bytestream2_get_byte(&g);
for (y = 0; y < 4; y++)
for (x = 0; x < 4; x++, pattern >>= 1)
cur[x + y*width] = (pattern & 1) ? b : a;
break;
case 1:
pattern = ~pattern;
case 2:
a = bytestream2_get_byte(&g);
for (y = 0; y < 4; y++)
for (x = 0; x < 4; x++, pattern >>= 1)
if (pattern & 1 && check_pixel(prev + x + y*width, pstart, pend))
cur[x + y*width] = prev[x + y*width];
else
cur[x + y*width] = a;
break;
case 3:
av_log(c->avctx, AV_LOG_ERROR, "Invalid opcode seen @%d\n", blk);
return AVERROR_INVALIDDATA;
}
break;
}
blocktypes <<= 2;
cur += 4;
prev += 4;
blk2++;
if (blk2 == (width >> 2)) {
blk2 = 0;
cur += width * 3;
prev += width * 3;
}
}
return 0;
}
static int decode_frame(AVCodecContext *avctx, AVFrame *frame,
int *got_frame, AVPacket *avpkt)
{
VBDecContext * const c = avctx->priv_data;
uint8_t *outptr, *srcptr;
int i, j, ret;
int flags;
uint32_t size;
int offset = 0;
if (avpkt->size < 2)
return AVERROR_INVALIDDATA;
bytestream2_init(&c->stream, avpkt->data, avpkt->size);
if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
return ret;
flags = bytestream2_get_le16(&c->stream);
if (flags & VB_HAS_GMC) {
i = (int16_t)bytestream2_get_le16(&c->stream);
j = (int16_t)bytestream2_get_le16(&c->stream);
if (FFABS(j) > avctx->height) {
av_log(avctx, AV_LOG_ERROR, "GMV out of range\n");
return AVERROR_INVALIDDATA;
}
offset = i + j * avctx->width;
}
if (flags & VB_HAS_VIDEO) {
size = bytestream2_get_le32(&c->stream);
if(size > bytestream2_get_bytes_left(&c->stream)+4 || size<4){
av_log(avctx, AV_LOG_ERROR, "Frame size invalid\n");
return -1;
}
vb_decode_framedata(c, offset);
bytestream2_skip(&c->stream, size - 4);
}
if (flags & VB_HAS_PALETTE) {
size = bytestream2_get_le32(&c->stream);
vb_decode_palette(c, size);
}
memcpy(frame->data[1], c->pal, AVPALETTE_SIZE);
frame->palette_has_changed = flags & VB_HAS_PALETTE;
outptr = frame->data[0];
srcptr = c->frame;
for (i = 0; i < avctx->height; i++) {
memcpy(outptr, srcptr, avctx->width);
srcptr += avctx->width;
outptr += frame->linesize[0];
}
FFSWAP(uint8_t*, c->frame, c->prev_frame);
*got_frame = 1;
/* always report that the buffer was completely consumed */
return avpkt->size;
}
static av_cold int decode_init(AVCodecContext *avctx)
{
VBDecContext * const c = avctx->priv_data;
c->avctx = avctx;
avctx->pix_fmt = AV_PIX_FMT_PAL8;
c->frame = av_mallocz(avctx->width * avctx->height);
c->prev_frame = av_mallocz(avctx->width * avctx->height);
if (!c->frame || !c->prev_frame)
return AVERROR(ENOMEM);
return 0;
}
static av_cold int decode_end(AVCodecContext *avctx)
{
VBDecContext *c = avctx->priv_data;
av_freep(&c->frame);
av_freep(&c->prev_frame);
return 0;
}
const FFCodec ff_vb_decoder = {
.p.name = "vb",
.p.long_name = NULL_IF_CONFIG_SMALL("Beam Software VB"),
.p.type = AVMEDIA_TYPE_VIDEO,
.p.id = AV_CODEC_ID_VB,
.priv_data_size = sizeof(VBDecContext),
.init = decode_init,
.close = decode_end,
FF_CODEC_DECODE_CB(decode_frame),
.p.capabilities = AV_CODEC_CAP_DR1,
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
};
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