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FFmpeg/libavcodec/midivid.c
Andreas Rheinhardt a247ac640d avcodec: Constify AVCodecs 
Given that the AVCodec.next pointer has now been removed, most of the
AVCodecs are not modified at all any more and can therefore be made
const (as this patch does); the only exceptions are the very few codecs
for external libraries that have a init_static_data callback.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>
2021-04-27 10:43:15 -03:00

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/*
* MidiVid decoder
* Copyright (c) 2019 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "libavutil/imgutils.h"
#include "libavutil/internal.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/mem.h"
#define BITSTREAM_READER_LE
#include "avcodec.h"
#include "get_bits.h"
#include "bytestream.h"
#include "internal.h"
typedef struct MidiVidContext {
GetByteContext gb;
uint8_t *uncompressed;
unsigned int uncompressed_size;
uint8_t *skip;
AVFrame *frame;
} MidiVidContext;
static int decode_mvdv(MidiVidContext *s, AVCodecContext *avctx, AVFrame *frame)
{
GetByteContext *gb = &s->gb;
GetBitContext mask;
GetByteContext idx9;
uint16_t nb_vectors, intra_flag;
const uint8_t *vec;
const uint8_t *mask_start;
uint8_t *skip;
uint32_t mask_size;
int idx9bits = 0;
int idx9val = 0;
uint32_t nb_blocks;
nb_vectors = bytestream2_get_le16(gb);
intra_flag = !!bytestream2_get_le16(gb);
if (intra_flag) {
nb_blocks = (avctx->width / 2) * (avctx->height / 2);
} else {
int ret, skip_linesize, padding;
nb_blocks = bytestream2_get_le32(gb);
skip_linesize = avctx->width >> 1;
mask_start = gb->buffer_start + bytestream2_tell(gb);
mask_size = (FFALIGN(avctx->width, 32) >> 2) * (avctx->height >> 2) >> 3;
padding = (FFALIGN(avctx->width, 32) - avctx->width) >> 2;
if (bytestream2_get_bytes_left(gb) < mask_size)
return AVERROR_INVALIDDATA;
ret = init_get_bits8(&mask, mask_start, mask_size);
if (ret < 0)
return ret;
bytestream2_skip(gb, mask_size);
skip = s->skip;
for (int y = 0; y < avctx->height >> 2; y++) {
for (int x = 0; x < avctx->width >> 2; x++) {
int flag = !get_bits1(&mask);
skip[(y*2) *skip_linesize + x*2 ] = flag;
skip[(y*2) *skip_linesize + x*2+1] = flag;
skip[(y*2+1)*skip_linesize + x*2 ] = flag;
skip[(y*2+1)*skip_linesize + x*2+1] = flag;
}
skip_bits_long(&mask, padding);
}
}
vec = gb->buffer_start + bytestream2_tell(gb);
if (bytestream2_get_bytes_left(gb) < nb_vectors * 12)
return AVERROR_INVALIDDATA;
bytestream2_skip(gb, nb_vectors * 12);
if (nb_vectors > 256) {
if (bytestream2_get_bytes_left(gb) < (nb_blocks + 7 * !intra_flag) / 8)
return AVERROR_INVALIDDATA;
bytestream2_init(&idx9, gb->buffer_start + bytestream2_tell(gb), (nb_blocks + 7 * !intra_flag) / 8);
bytestream2_skip(gb, (nb_blocks + 7 * !intra_flag) / 8);
}
skip = s->skip;
for (int y = avctx->height - 2; y >= 0; y -= 2) {
uint8_t *dsty = frame->data[0] + y * frame->linesize[0];
uint8_t *dstu = frame->data[1] + y * frame->linesize[1];
uint8_t *dstv = frame->data[2] + y * frame->linesize[2];
for (int x = 0; x < avctx->width; x += 2) {
int idx;
if (!intra_flag && *skip++)
continue;
if (bytestream2_get_bytes_left(gb) <= 0)
return AVERROR_INVALIDDATA;
if (nb_vectors <= 256) {
idx = bytestream2_get_byte(gb);
} else {
if (idx9bits == 0) {
idx9val = bytestream2_get_byte(&idx9);
idx9bits = 8;
}
idx9bits--;
idx = bytestream2_get_byte(gb) | (((idx9val >> (7 - idx9bits)) & 1) << 8);
}
if (idx >= nb_vectors)
return AVERROR_INVALIDDATA;
dsty[x +frame->linesize[0]] = vec[idx * 12 + 0];
dsty[x+1+frame->linesize[0]] = vec[idx * 12 + 3];
dsty[x] = vec[idx * 12 + 6];
dsty[x+1] = vec[idx * 12 + 9];
dstu[x +frame->linesize[1]] = vec[idx * 12 + 1];
dstu[x+1+frame->linesize[1]] = vec[idx * 12 + 4];
dstu[x] = vec[idx * 12 + 7];
dstu[x+1] = vec[idx * 12 +10];
dstv[x +frame->linesize[2]] = vec[idx * 12 + 2];
dstv[x+1+frame->linesize[2]] = vec[idx * 12 + 5];
dstv[x] = vec[idx * 12 + 8];
dstv[x+1] = vec[idx * 12 +11];
}
}
return intra_flag;
}
static ptrdiff_t lzss_uncompress(MidiVidContext *s, GetByteContext *gb, uint8_t *dst, unsigned int size)
{
uint8_t *dst_start = dst;
uint8_t *dst_end = dst + size;
for (;bytestream2_get_bytes_left(gb) >= 3;) {
int op = bytestream2_get_le16(gb);
for (int i = 0; i < 16; i++) {
if (op & 1) {
int s0 = bytestream2_get_byte(gb);
int s1 = bytestream2_get_byte(gb);
int offset = ((s0 & 0xF0) << 4) | s1;
int length = (s0 & 0xF) + 3;
if (dst + length > dst_end ||
dst - offset < dst_start)
return AVERROR_INVALIDDATA;
if (offset > 0) {
for (int j = 0; j < length; j++) {
dst[j] = dst[j - offset];
}
}
dst += length;
} else {
if (dst >= dst_end)
return AVERROR_INVALIDDATA;
*dst++ = bytestream2_get_byte(gb);
}
op >>= 1;
}
}
return dst - dst_start;
}
static int decode_frame(AVCodecContext *avctx, void *data,
int *got_frame, AVPacket *avpkt)
{
MidiVidContext *s = avctx->priv_data;
GetByteContext *gb = &s->gb;
AVFrame *frame = s->frame;
int ret, key, uncompressed;
if (avpkt->size <= 13)
return AVERROR_INVALIDDATA;
bytestream2_init(gb, avpkt->data, avpkt->size);
bytestream2_skip(gb, 8);
uncompressed = bytestream2_get_le32(gb);
if ((ret = ff_reget_buffer(avctx, s->frame, 0)) < 0)
return ret;
if (uncompressed) {
ret = decode_mvdv(s, avctx, frame);
} else {
av_fast_padded_malloc(&s->uncompressed, &s->uncompressed_size, 16LL * (avpkt->size - 12));
if (!s->uncompressed)
return AVERROR(ENOMEM);
ret = lzss_uncompress(s, gb, s->uncompressed, s->uncompressed_size);
if (ret < 0)
return ret;
bytestream2_init(gb, s->uncompressed, ret);
ret = decode_mvdv(s, avctx, frame);
}
if (ret < 0)
return ret;
key = ret;
if ((ret = av_frame_ref(data, s->frame)) < 0)
return ret;
frame->pict_type = key ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
frame->key_frame = key;
*got_frame = 1;
return avpkt->size;
}
static av_cold int decode_init(AVCodecContext *avctx)
{
MidiVidContext *s = avctx->priv_data;
int ret = av_image_check_size(avctx->width, avctx->height, 0, avctx);
if (avctx->width & 3 || avctx->height & 3)
ret = AVERROR_INVALIDDATA;
if (ret < 0) {
av_log(avctx, AV_LOG_ERROR, "Invalid image size %dx%d.\n",
avctx->width, avctx->height);
return ret;
}
avctx->pix_fmt = AV_PIX_FMT_YUV444P;
s->frame = av_frame_alloc();
if (!s->frame)
return AVERROR(ENOMEM);
s->skip = av_calloc(avctx->width >> 1, avctx->height >> 1);
if (!s->skip)
return AVERROR(ENOMEM);
return 0;
}
static void decode_flush(AVCodecContext *avctx)
{
MidiVidContext *s = avctx->priv_data;
av_frame_unref(s->frame);
}
static av_cold int decode_close(AVCodecContext *avctx)
{
MidiVidContext *s = avctx->priv_data;
av_frame_free(&s->frame);
av_freep(&s->uncompressed);
av_freep(&s->skip);
return 0;
}
const AVCodec ff_mvdv_decoder = {
.name = "mvdv",
.long_name = NULL_IF_CONFIG_SMALL("MidiVid VQ"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_MVDV,
.priv_data_size = sizeof(MidiVidContext),
.init = decode_init,
.decode = decode_frame,
.flush = decode_flush,
.close = decode_close,
.capabilities = AV_CODEC_CAP_DR1,
.caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
};
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