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FFmpeg/libavcodec/qpeg.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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/*
* QPEG codec
* Copyright (c) 2004 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
* QPEG codec.
*/
#include "avcodec.h"
#include "bytestream.h"
#include "codec_internal.h"
#include "decode.h"
#include "internal.h"
typedef struct QpegContext{
AVCodecContext *avctx;
AVFrame *ref;
uint32_t pal[256];
GetByteContext buffer;
} QpegContext;
static void qpeg_decode_intra(QpegContext *qctx, uint8_t *dst,
int stride, int width, int height)
{
int i;
int code;
int c0, c1;
int run, copy;
int filled = 0;
int rows_to_go;
rows_to_go = height;
height--;
dst = dst + height * stride;
while ((bytestream2_get_bytes_left(&qctx->buffer) > 0) && (rows_to_go > 0)) {
code = bytestream2_get_byte(&qctx->buffer);
run = copy = 0;
if(code == 0xFC) /* end-of-picture code */
break;
if(code >= 0xF8) { /* very long run */
c0 = bytestream2_get_byte(&qctx->buffer);
c1 = bytestream2_get_byte(&qctx->buffer);
run = ((code & 0x7) << 16) + (c0 << 8) + c1 + 2;
} else if (code >= 0xF0) { /* long run */
c0 = bytestream2_get_byte(&qctx->buffer);
run = ((code & 0xF) << 8) + c0 + 2;
} else if (code >= 0xE0) { /* short run */
run = (code & 0x1F) + 2;
} else if (code >= 0xC0) { /* very long copy */
c0 = bytestream2_get_byte(&qctx->buffer);
c1 = bytestream2_get_byte(&qctx->buffer);
copy = ((code & 0x3F) << 16) + (c0 << 8) + c1 + 1;
} else if (code >= 0x80) { /* long copy */
c0 = bytestream2_get_byte(&qctx->buffer);
copy = ((code & 0x7F) << 8) + c0 + 1;
} else { /* short copy */
copy = code + 1;
}
/* perform actual run or copy */
if(run) {
int p;
p = bytestream2_get_byte(&qctx->buffer);
for(i = 0; i < run; i++) {
int step = FFMIN(run - i, width - filled);
memset(dst+filled, p, step);
filled += step;
i += step - 1;
if (filled >= width) {
filled = 0;
dst -= stride;
rows_to_go--;
while (run - i > width && rows_to_go > 0) {
memset(dst, p, width);
dst -= stride;
rows_to_go--;
i += width;
}
if(rows_to_go <= 0)
break;
}
}
} else {
if (bytestream2_get_bytes_left(&qctx->buffer) < copy)
copy = bytestream2_get_bytes_left(&qctx->buffer);
while (copy > 0) {
int step = FFMIN(copy, width - filled);
bytestream2_get_bufferu(&qctx->buffer, dst + filled, step);
filled += step;
copy -= step;
if (filled >= width) {
filled = 0;
dst -= stride;
rows_to_go--;
if(rows_to_go <= 0)
break;
}
}
}
}
}
static const uint8_t qpeg_table_h[16] =
{ 0x00, 0x20, 0x20, 0x20, 0x18, 0x10, 0x10, 0x20, 0x10, 0x08, 0x18, 0x08, 0x08, 0x18, 0x10, 0x04};
static const uint8_t qpeg_table_w[16] =
{ 0x00, 0x20, 0x18, 0x08, 0x18, 0x10, 0x20, 0x10, 0x08, 0x10, 0x20, 0x20, 0x08, 0x10, 0x18, 0x04};
/* Decodes delta frames */
static void av_noinline qpeg_decode_inter(QpegContext *qctx, uint8_t *dst,
int stride, int width, int height,
int delta, const uint8_t *ctable,
uint8_t *refdata)
{
int i, j;
int code;
int filled = 0;
int orig_height;
if (refdata) {
/* copy prev frame */
for (i = 0; i < height; i++)
memcpy(dst + (i * stride), refdata + (i * stride), width);
} else {
refdata = dst;
}
orig_height = height;
height--;
dst = dst + height * stride;
while ((bytestream2_get_bytes_left(&qctx->buffer) > 0) && (height >= 0)) {
code = bytestream2_get_byte(&qctx->buffer);
if(delta) {
/* motion compensation */
while(bytestream2_get_bytes_left(&qctx->buffer) > 0 && (code & 0xF0) == 0xF0) {
if(delta == 1) {
int me_idx;
int me_w, me_h, me_x, me_y;
uint8_t *me_plane;
int corr, val;
/* get block size by index */
me_idx = code & 0xF;
me_w = qpeg_table_w[me_idx];
me_h = qpeg_table_h[me_idx];
/* extract motion vector */
corr = bytestream2_get_byte(&qctx->buffer);
val = corr >> 4;
if(val > 7)
val -= 16;
me_x = val;
val = corr & 0xF;
if(val > 7)
val -= 16;
me_y = val;
/* check motion vector */
if ((me_x + filled < 0) || (me_x + me_w + filled > width) ||
(height - me_y - me_h < 0) || (height - me_y >= orig_height) ||
(filled + me_w > width) || (height - me_h < 0))
av_log(qctx->avctx, AV_LOG_ERROR, "Bogus motion vector (%i,%i), block size %ix%i at %i,%i\n",
me_x, me_y, me_w, me_h, filled, height);
else {
/* do motion compensation */
me_plane = refdata + (filled + me_x) + (height - me_y) * stride;
for(j = 0; j < me_h; j++) {
for(i = 0; i < me_w; i++)
dst[filled + i - (j * stride)] = me_plane[i - (j * stride)];
}
}
}
code = bytestream2_get_byte(&qctx->buffer);
}
}
if(code == 0xE0) /* end-of-picture code */
break;
if(code > 0xE0) { /* run code: 0xE1..0xFF */
int p;
code &= 0x1F;
p = bytestream2_get_byte(&qctx->buffer);
for(i = 0; i <= code; i++) {
dst[filled++] = p;
if(filled >= width) {
filled = 0;
dst -= stride;
height--;
if (height < 0)
break;
}
}
} else if(code >= 0xC0) { /* copy code: 0xC0..0xDF */
code &= 0x1F;
if(code + 1 > bytestream2_get_bytes_left(&qctx->buffer))
break;
for(i = 0; i <= code; i++) {
dst[filled++] = bytestream2_get_byte(&qctx->buffer);
if(filled >= width) {
filled = 0;
dst -= stride;
height--;
if (height < 0)
break;
}
}
} else if(code >= 0x80) { /* skip code: 0x80..0xBF */
int skip;
code &= 0x3F;
/* codes 0x80 and 0x81 are actually escape codes,
skip value minus constant is in the next byte */
if(!code)
skip = bytestream2_get_byte(&qctx->buffer) + 64;
else if(code == 1)
skip = bytestream2_get_byte(&qctx->buffer) + 320;
else
skip = code;
filled += skip;
while( filled >= width) {
filled -= width;
dst -= stride;
height--;
if(height < 0)
break;
}
} else {
/* zero code treated as one-pixel skip */
if(code) {
dst[filled++] = ctable[code & 0x7F];
}
else
filled++;
if(filled >= width) {
filled = 0;
dst -= stride;
height--;
}
}
}
}
static int decode_frame(AVCodecContext *avctx,
void *data, int *got_frame,
AVPacket *avpkt)
{
uint8_t ctable[128];
QpegContext * const a = avctx->priv_data;
AVFrame * const p = data;
AVFrame * const ref = a->ref;
uint8_t* outdata;
int delta, intra, ret;
if (avpkt->size < 0x86) {
av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
return AVERROR_INVALIDDATA;
}
bytestream2_init(&a->buffer, avpkt->data, avpkt->size);
if ((ret = ff_get_buffer(avctx, p, AV_GET_BUFFER_FLAG_REF)) < 0)
return ret;
outdata = p->data[0];
bytestream2_skip(&a->buffer, 4);
bytestream2_get_buffer(&a->buffer, ctable, 128);
bytestream2_skip(&a->buffer, 1);
delta = bytestream2_get_byte(&a->buffer);
intra = delta == 0x10;
if (intra) {
qpeg_decode_intra(a, outdata, p->linesize[0], avctx->width, avctx->height);
} else {
qpeg_decode_inter(a, outdata, p->linesize[0], avctx->width, avctx->height, delta, ctable, ref->data[0]);
}
/* make the palette available on the way out */
p->palette_has_changed = ff_copy_palette(a->pal, avpkt, avctx);
memcpy(p->data[1], a->pal, AVPALETTE_SIZE);
av_frame_unref(ref);
if ((ret = av_frame_ref(ref, p)) < 0)
return ret;
p->key_frame = intra;
p->pict_type = intra ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
*got_frame = 1;
return avpkt->size;
}
static void decode_flush(AVCodecContext *avctx){
QpegContext * const a = avctx->priv_data;
int i, pal_size;
const uint8_t *pal_src;
av_frame_unref(a->ref);
pal_size = FFMIN(1024U, avctx->extradata_size);
pal_src = avctx->extradata + avctx->extradata_size - pal_size;
for (i=0; i<pal_size/4; i++)
a->pal[i] = 0xFFU<<24 | AV_RL32(pal_src+4*i);
}
static av_cold int decode_end(AVCodecContext *avctx)
{
QpegContext * const a = avctx->priv_data;
av_frame_free(&a->ref);
return 0;
}
static av_cold int decode_init(AVCodecContext *avctx){
QpegContext * const a = avctx->priv_data;
a->avctx = avctx;
avctx->pix_fmt= AV_PIX_FMT_PAL8;
a->ref = av_frame_alloc();
if (!a->ref)
return AVERROR(ENOMEM);
decode_flush(avctx);
return 0;
}
const FFCodec ff_qpeg_decoder = {
.p.name = "qpeg",
.p.long_name = NULL_IF_CONFIG_SMALL("Q-team QPEG"),
.p.type = AVMEDIA_TYPE_VIDEO,
.p.id = AV_CODEC_ID_QPEG,
.priv_data_size = sizeof(QpegContext),
.init = decode_init,
.close = decode_end,
.decode = decode_frame,
.flush = decode_flush,
.p.capabilities = AV_CODEC_CAP_DR1,
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE |
FF_CODEC_CAP_INIT_CLEANUP,
};
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