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FFmpeg/libavcodec/gdv.c
Andreas Rheinhardt 20f9727018 avcodec/codec_internal: Add FFCodec, hide internal part of AVCodec 
Up until now, codec.h contains both public and private parts
of AVCodec. This exposes the internals of AVCodec to users
and leads them into the temptation of actually using them
and forces us to forward-declare structures and types that
users can't use at all.

This commit changes this by adding a new structure FFCodec to
codec_internal.h that extends AVCodec, i.e. contains the public
AVCodec as first member; the private fields of AVCodec are moved
to this structure, leaving codec.h clean.

Reviewed-by: Anton Khirnov <anton@khirnov.net>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2022-03-21 01:33:09 +01:00

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/*
* Gremlin Digital Video (GDV) decoder
* Copyright (c) 2017 Konstantin Shishkov
* Copyright (c) 2017 Paul B Mahol
*
* 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
*/
#include "libavutil/common.h"
#include "avcodec.h"
#include "bytestream.h"
#include "codec_internal.h"
#include "decode.h"
#include "internal.h"
typedef struct GDVContext {
AVCodecContext *avctx;
GetByteContext gb;
GetByteContext g2;
PutByteContext pb;
uint32_t pal[256];
uint8_t *frame;
unsigned frame_size;
unsigned scale_h, scale_v;
} GDVContext;
typedef struct Bits8 {
uint8_t queue;
uint8_t fill;
} Bits8;
typedef struct Bits32 {
uint32_t queue;
uint8_t fill;
} Bits32;
#define PREAMBLE_SIZE 4096
static av_cold int gdv_decode_init(AVCodecContext *avctx)
{
GDVContext *gdv = avctx->priv_data;
int i, j, k;
avctx->pix_fmt = AV_PIX_FMT_PAL8;
gdv->frame_size = avctx->width * avctx->height + PREAMBLE_SIZE;
gdv->frame = av_calloc(gdv->frame_size, 1);
if (!gdv->frame)
return AVERROR(ENOMEM);
for (i = 0; i < 2; i++) {
for (j = 0; j < 256; j++) {
for (k = 0; k < 8; k++) {
gdv->frame[i * 2048 + j * 8 + k] = j;
}
}
}
return 0;
}
static void scaleup(uint8_t *dst, const uint8_t *src, int w)
{
int x;
for (x = 0; x < w - 7; x+=8) {
dst[x + 0] =
dst[x + 1] = src[(x>>1) + 0];
dst[x + 2] =
dst[x + 3] = src[(x>>1) + 1];
dst[x + 4] =
dst[x + 5] = src[(x>>1) + 2];
dst[x + 6] =
dst[x + 7] = src[(x>>1) + 3];
}
for (; x < w; x++) {
dst[x] = src[(x>>1)];
}
}
static void scaleup_rev(uint8_t *dst, const uint8_t *src, int w)
{
int x;
for (x = w - 1; (x+1) & 7; x--) {
dst[x] = src[(x>>1)];
}
for (x -= 7; x >= 0; x -= 8) {
dst[x + 6] =
dst[x + 7] = src[(x>>1) + 3];
dst[x + 4] =
dst[x + 5] = src[(x>>1) + 2];
dst[x + 2] =
dst[x + 3] = src[(x>>1) + 1];
dst[x + 0] =
dst[x + 1] = src[(x>>1) + 0];
}
}
static void scaledown(uint8_t *dst, const uint8_t *src, int w)
{
int x;
for (x = 0; x < w - 7; x+=8) {
dst[x + 0] = src[2*x + 0];
dst[x + 1] = src[2*x + 2];
dst[x + 2] = src[2*x + 4];
dst[x + 3] = src[2*x + 6];
dst[x + 4] = src[2*x + 8];
dst[x + 5] = src[2*x +10];
dst[x + 6] = src[2*x +12];
dst[x + 7] = src[2*x +14];
}
for (; x < w; x++) {
dst[x] = src[2*x];
}
}
static void rescale(GDVContext *gdv, uint8_t *dst, int w, int h, int scale_v, int scale_h)
{
int j, y;
if ((gdv->scale_v == scale_v) && (gdv->scale_h == scale_h)) {
return;
}
if (gdv->scale_v) {
for (j = 0; j < h; j++) {
int y = h - j - 1;
uint8_t *dst1 = dst + PREAMBLE_SIZE + y * w;
uint8_t *src1 = dst + PREAMBLE_SIZE + (y>>!!gdv->scale_h) * (w>>1);
scaleup_rev(dst1, src1, w);
}
} else if (gdv->scale_h) {
for (j = 0; j < h; j++) {
int y = h - j - 1;
uint8_t *dst1 = dst + PREAMBLE_SIZE + y * w;
uint8_t *src1 = dst + PREAMBLE_SIZE + (y>>1) * w;
memcpy(dst1, src1, w);
}
}
if (scale_h && scale_v) {
for (y = 0; y < (h>>1); y++) {
uint8_t *dst1 = dst + PREAMBLE_SIZE + y * (w>>1);
uint8_t *src1 = dst + PREAMBLE_SIZE + y*2 * w;
scaledown(dst1, src1, w>>1);
}
} else if (scale_h) {
for (y = 0; y < (h>>1); y++) {
uint8_t *dst1 = dst + PREAMBLE_SIZE + y * w;
uint8_t *src1 = dst + PREAMBLE_SIZE + y*2 * w;
memcpy(dst1, src1, w);
}
} else if (scale_v) {
for (y = 0; y < h; y++) {
uint8_t *dst1 = dst + PREAMBLE_SIZE + y * w;
scaledown(dst1, dst1, w>>1);
}
}
gdv->scale_v = scale_v;
gdv->scale_h = scale_h;
}
static int read_bits2(Bits8 *bits, GetByteContext *gb)
{
int res;
if (bits->fill == 0) {
bits->queue |= bytestream2_get_byte(gb);
bits->fill = 8;
}
res = bits->queue >> 6;
bits->queue <<= 2;
bits->fill -= 2;
return res;
}
static void fill_bits32(Bits32 *bits, GetByteContext *gb)
{
bits->queue = bytestream2_get_le32(gb);
bits->fill = 32;
}
static int read_bits32(Bits32 *bits, GetByteContext *gb, int nbits)
{
int res = bits->queue & ((1 << nbits) - 1);
bits->queue >>= nbits;
bits->fill -= nbits;
if (bits->fill <= 16) {
bits->queue |= bytestream2_get_le16(gb) << bits->fill;
bits->fill += 16;
}
return res;
}
static void lz_copy(PutByteContext *pb, GetByteContext *g2, int offset, unsigned len)
{
int i;
if (offset == -1) {
int c;
bytestream2_seek(g2, bytestream2_tell_p(pb) - 1, SEEK_SET);
c = bytestream2_get_byte(g2);
for (i = 0; i < len; i++) {
bytestream2_put_byte(pb, c);
}
} else if (offset < 0) {
int start = bytestream2_tell_p(pb) - (-offset);
bytestream2_seek(g2, start, SEEK_SET);
for (i = 0; i < len; i++) {
bytestream2_put_byte(pb, bytestream2_get_byte(g2));
}
} else {
int start = bytestream2_tell_p(pb) + offset;
bytestream2_seek(g2, start, SEEK_SET);
for (i = 0; i < len; i++) {
bytestream2_put_byte(pb, bytestream2_get_byte(g2));
}
}
}
static int decompress_2(AVCodecContext *avctx)
{
GDVContext *gdv = avctx->priv_data;
GetByteContext *gb = &gdv->gb;
GetByteContext *g2 = &gdv->g2;
PutByteContext *pb = &gdv->pb;
Bits8 bits = { 0 };
int c, i;
bytestream2_init(g2, gdv->frame, gdv->frame_size);
bytestream2_skip_p(pb, PREAMBLE_SIZE);
for (c = 0; c < 256; c++) {
for (i = 0; i < 16; i++) {
gdv->frame[c * 16 + i] = c;
}
}
while (bytestream2_get_bytes_left_p(pb) > 0 && bytestream2_get_bytes_left(gb) > 0) {
int tag = read_bits2(&bits, gb);
if (tag == 0) {
bytestream2_put_byte(pb, bytestream2_get_byte(gb));
} else if (tag == 1) {
int b = bytestream2_get_byte(gb);
int len = (b & 0xF) + 3;
int top = (b >> 4) & 0xF;
int off = (bytestream2_get_byte(gb) << 4) + top - 4096;
lz_copy(pb, g2, off, len);
} else if (tag == 2) {
int len = (bytestream2_get_byte(gb)) + 2;
bytestream2_skip_p(pb, len);
} else {
break;
}
}
if (bytestream2_get_bytes_left_p(pb) > 0)
return AVERROR_INVALIDDATA;
return 0;
}
static int decompress_5(AVCodecContext *avctx, unsigned skip)
{
GDVContext *gdv = avctx->priv_data;
GetByteContext *gb = &gdv->gb;
GetByteContext *g2 = &gdv->g2;
PutByteContext *pb = &gdv->pb;
Bits8 bits = { 0 };
bytestream2_init(g2, gdv->frame, gdv->frame_size);
bytestream2_skip_p(pb, skip + PREAMBLE_SIZE);
while (bytestream2_get_bytes_left_p(pb) > 0 && bytestream2_get_bytes_left(gb) > 0) {
int tag = read_bits2(&bits, gb);
if (bytestream2_get_bytes_left(gb) < 1)
return AVERROR_INVALIDDATA;
if (tag == 0) {
bytestream2_put_byte(pb, bytestream2_get_byte(gb));
} else if (tag == 1) {
int b = bytestream2_get_byte(gb);
int len = (b & 0xF) + 3;
int top = b >> 4;
int off = (bytestream2_get_byte(gb) << 4) + top - 4096;
lz_copy(pb, g2, off, len);
} else if (tag == 2) {
int len;
int b = bytestream2_get_byte(gb);
if (b == 0) {
return 0;
}
if (b != 0xFF) {
len = b;
} else {
len = bytestream2_get_le16(gb);
}
bytestream2_skip_p(pb, len + 1);
} else {
int b = bytestream2_get_byte(gb);
int len = (b & 0x3) + 2;
int off = -(b >> 2) - 1;
lz_copy(pb, g2, off, len);
}
}
if (bytestream2_get_bytes_left_p(pb) > 0)
return AVERROR_INVALIDDATA;
return 0;
}
static int decompress_68(AVCodecContext *avctx, unsigned skip, unsigned use8)
{
GDVContext *gdv = avctx->priv_data;
GetByteContext *gb = &gdv->gb;
GetByteContext *g2 = &gdv->g2;
PutByteContext *pb = &gdv->pb;
Bits32 bits;
bytestream2_init(g2, gdv->frame, gdv->frame_size);
bytestream2_skip_p(pb, skip + PREAMBLE_SIZE);
fill_bits32(&bits, gb);
while (bytestream2_get_bytes_left_p(pb) > 0 && bytestream2_get_bytes_left(gb) > 0) {
int tag = read_bits32(&bits, gb, 2);
if (tag == 0) {
int b = read_bits32(&bits, gb, 1);
if (b == 0) {
bytestream2_put_byte(pb, bytestream2_get_byte(gb));
} else {
int i, len = 2;
int lbits = 0;
while (1) {
int val;
lbits += 1;
val = read_bits32(&bits, gb, lbits);
len += val;
if (val != ((1 << lbits) - 1)) {
break;
}
if (lbits >= 16)
return AVERROR_INVALIDDATA;
}
for (i = 0; i < len; i++) {
bytestream2_put_byte(pb, bytestream2_get_byte(gb));
}
}
} else if (tag == 1) {
int b = read_bits32(&bits, gb, 1);
int len;
if (b == 0) {
len = (read_bits32(&bits, gb, 4)) + 2;
} else {
int bb = bytestream2_get_byte(gb);
if ((bb & 0x80) == 0) {
len = bb + 18;
} else {
int top = (bb & 0x7F) << 8;
len = top + bytestream2_get_byte(gb) + 146;
}
}
bytestream2_skip_p(pb, len);
} else if (tag == 2) {
int i, subtag = read_bits32(&bits, gb, 2);
if (subtag != 3) {
int top = (read_bits32(&bits, gb, 4)) << 8;
int offs = top + bytestream2_get_byte(gb);
if ((subtag != 0) || (offs <= 0xF80)) {
int len = (subtag) + 3;
lz_copy(pb, g2, (offs) - 4096, len);
} else {
int real_off, len, c1, c2;
if (offs == 0xFFF) {
return 0;
}
real_off = ((offs >> 4) & 0x7) + 1;
len = ((offs & 0xF) + 2) * 2;
c1 = gdv->frame[bytestream2_tell_p(pb) - real_off];
c2 = gdv->frame[bytestream2_tell_p(pb) - real_off + 1];
for (i = 0; i < len/2; i++) {
bytestream2_put_byte(pb, c1);
bytestream2_put_byte(pb, c2);
}
}
} else {
int b = bytestream2_get_byte(gb);
int off = ((b & 0x7F)) + 1;
int len = ((b & 0x80) == 0) ? 2 : 3;
lz_copy(pb, g2, -off, len);
}
} else {
int len;
int off;
if (use8) {
int q, b = bytestream2_get_byte(gb);
if ((b & 0xC0) == 0xC0) {
len = ((b & 0x3F)) + 8;
q = read_bits32(&bits, gb, 4);
off = (q << 8) + (bytestream2_get_byte(gb)) + 1;
} else {
int ofs1;
if ((b & 0x80) == 0) {
len = ((b >> 4)) + 6;
ofs1 = (b & 0xF);
} else {
len = ((b & 0x3F)) + 14;
ofs1 = read_bits32(&bits, gb, 4);
}
off = (ofs1 << 8) + (bytestream2_get_byte(gb)) - 4096;
}
} else {
int ofs1, b = bytestream2_get_byte(gb);
if ((b >> 4) == 0xF) {
len = bytestream2_get_byte(gb) + 21;
} else {
len = (b >> 4) + 6;
}
ofs1 = (b & 0xF);
off = (ofs1 << 8) + bytestream2_get_byte(gb) - 4096;
}
lz_copy(pb, g2, off, len);
}
}
if (bytestream2_get_bytes_left_p(pb) > 0)
return AVERROR_INVALIDDATA;
return 0;
}
static int gdv_decode_frame(AVCodecContext *avctx, void *data,
int *got_frame, AVPacket *avpkt)
{
GDVContext *gdv = avctx->priv_data;
GetByteContext *gb = &gdv->gb;
PutByteContext *pb = &gdv->pb;
AVFrame *frame = data;
int ret, i;
int compression;
unsigned flags;
uint8_t *dst;
bytestream2_init(gb, avpkt->data, avpkt->size);
bytestream2_init_writer(pb, gdv->frame, gdv->frame_size);
flags = bytestream2_get_le32(gb);
compression = flags & 0xF;
if (compression == 4 || compression == 7 || compression > 8)
return AVERROR_INVALIDDATA;
if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
return ret;
ff_copy_palette(gdv->pal, avpkt, avctx);
if (compression < 2 && bytestream2_get_bytes_left(gb) < 256*3)
return AVERROR_INVALIDDATA;
rescale(gdv, gdv->frame, avctx->width, avctx->height,
!!(flags & 0x10), !!(flags & 0x20));
switch (compression) {
case 1:
memset(gdv->frame + PREAMBLE_SIZE, 0, gdv->frame_size - PREAMBLE_SIZE);
case 0:
for (i = 0; i < 256; i++) {
unsigned r = bytestream2_get_byte(gb);
unsigned g = bytestream2_get_byte(gb);
unsigned b = bytestream2_get_byte(gb);
gdv->pal[i] = 0xFFU << 24 | r << 18 | g << 10 | b << 2;
}
break;
case 2:
ret = decompress_2(avctx);
break;
case 3:
break;
case 5:
ret = decompress_5(avctx, flags >> 8);
break;
case 6:
ret = decompress_68(avctx, flags >> 8, 0);
break;
case 8:
ret = decompress_68(avctx, flags >> 8, 1);
break;
default:
av_assert0(0);
}
if (ret < 0)
return ret;
memcpy(frame->data[1], gdv->pal, AVPALETTE_SIZE);
dst = frame->data[0];
if (!gdv->scale_v && !gdv->scale_h) {
int sidx = PREAMBLE_SIZE, didx = 0;
int y;
for (y = 0; y < avctx->height; y++) {
memcpy(dst + didx, gdv->frame + sidx, avctx->width);
sidx += avctx->width;
didx += frame->linesize[0];
}
} else {
int sidx = PREAMBLE_SIZE, didx = 0;
int y;
for (y = 0; y < avctx->height; y++) {
if (!gdv->scale_v) {
memcpy(dst + didx, gdv->frame + sidx, avctx->width);
} else {
uint8_t *dst2 = dst + didx;
uint8_t *src2 = gdv->frame + sidx;
scaleup(dst2, src2, avctx->width);
}
if (!gdv->scale_h || ((y & 1) == 1)) {
sidx += !gdv->scale_v ? avctx->width : avctx->width/2;
}
didx += frame->linesize[0];
}
}
*got_frame = 1;
return avpkt->size;
}
static av_cold int gdv_decode_close(AVCodecContext *avctx)
{
GDVContext *gdv = avctx->priv_data;
av_freep(&gdv->frame);
return 0;
}
const FFCodec ff_gdv_decoder = {
.p.name = "gdv",
.p.long_name = NULL_IF_CONFIG_SMALL("Gremlin Digital Video"),
.p.type = AVMEDIA_TYPE_VIDEO,
.p.id = AV_CODEC_ID_GDV,
.priv_data_size = sizeof(GDVContext),
.init = gdv_decode_init,
.close = gdv_decode_close,
.decode = gdv_decode_frame,
.p.capabilities = AV_CODEC_CAP_DR1,
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
};
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