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FFmpeg/libavcodec/midivid.c

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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;
}
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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