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FFmpeg/libavcodec/mvha.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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/*
* MidiVid Archive codec
*
* 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>
#define CACHED_BITSTREAM_READER !ARCH_X86_32
#include "libavutil/intreadwrite.h"
#include "avcodec.h"
#include "bytestream.h"
#include "codec_internal.h"
#include "get_bits.h"
#include "internal.h"
#include "lossless_videodsp.h"
#include "zlib_wrapper.h"
#include <zlib.h>
typedef struct MVHAContext {
GetBitContext gb;
int nb_symbols;
uint8_t symb[256];
uint32_t prob[256];
VLC vlc;
FFZStream zstream;
LLVidDSPContext llviddsp;
} MVHAContext;
typedef struct Node {
int16_t sym;
int16_t n0;
int16_t l, r;
uint32_t count;
} Node;
static void get_tree_codes(uint32_t *bits, int16_t *lens, uint8_t *xlat,
Node *nodes, int node,
uint32_t pfx, int pl, int *pos)
{
int s;
s = nodes[node].sym;
if (s != -1) {
bits[*pos] = (~pfx) & ((1ULL << FFMAX(pl, 1)) - 1);
lens[*pos] = FFMAX(pl, 1);
xlat[*pos] = s + (pl == 0);
(*pos)++;
} else {
pfx <<= 1;
pl++;
get_tree_codes(bits, lens, xlat, nodes, nodes[node].l, pfx, pl,
pos);
pfx |= 1;
get_tree_codes(bits, lens, xlat, nodes, nodes[node].r, pfx, pl,
pos);
}
}
static int build_vlc(AVCodecContext *avctx, VLC *vlc)
{
MVHAContext *s = avctx->priv_data;
Node nodes[512];
uint32_t bits[256];
int16_t lens[256];
uint8_t xlat[256];
int cur_node, i, j, pos = 0;
ff_free_vlc(vlc);
for (i = 0; i < s->nb_symbols; i++) {
nodes[i].count = s->prob[i];
nodes[i].sym = s->symb[i];
nodes[i].n0 = -2;
nodes[i].l = i;
nodes[i].r = i;
}
cur_node = s->nb_symbols;
j = 0;
do {
for (i = 0; ; i++) {
int new_node = j;
int first_node = cur_node;
int second_node = cur_node;
unsigned nd, st;
nodes[cur_node].count = -1;
do {
int val = nodes[new_node].count;
if (val && (val < nodes[first_node].count)) {
if (val >= nodes[second_node].count) {
first_node = new_node;
} else {
first_node = second_node;
second_node = new_node;
}
}
new_node += 1;
} while (new_node != cur_node);
if (first_node == cur_node)
break;
nd = nodes[second_node].count;
st = nodes[first_node].count;
nodes[second_node].count = 0;
nodes[first_node].count = 0;
if (nd >= UINT32_MAX - st) {
av_log(avctx, AV_LOG_ERROR, "count overflow\n");
return AVERROR_INVALIDDATA;
}
nodes[cur_node].count = nd + st;
nodes[cur_node].sym = -1;
nodes[cur_node].n0 = cur_node;
nodes[cur_node].l = first_node;
nodes[cur_node].r = second_node;
cur_node++;
}
j++;
} while (cur_node - s->nb_symbols == j);
get_tree_codes(bits, lens, xlat, nodes, cur_node - 1, 0, 0, &pos);
return ff_init_vlc_sparse(vlc, 12, pos, lens, 2, 2, bits, 4, 4, xlat, 1, 1, 0);
}
static int decode_frame(AVCodecContext *avctx, AVFrame *frame,
int *got_frame, AVPacket *avpkt)
{
MVHAContext *s = avctx->priv_data;
uint32_t type, size;
int ret;
if (avpkt->size <= 8)
return AVERROR_INVALIDDATA;
type = AV_RB32(avpkt->data);
size = AV_RL32(avpkt->data + 4);
if (size < 1 || size >= avpkt->size)
return AVERROR_INVALIDDATA;
if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
return ret;
if (type == MKTAG('L','Z','Y','V')) {
z_stream *const zstream = &s->zstream.zstream;
ret = inflateReset(zstream);
if (ret != Z_OK) {
av_log(avctx, AV_LOG_ERROR, "Inflate reset error: %d\n", ret);
return AVERROR_EXTERNAL;
}
zstream->next_in = avpkt->data + 8;
zstream->avail_in = avpkt->size - 8;
for (int p = 0; p < 3; p++) {
for (int y = 0; y < avctx->height; y++) {
zstream->next_out = frame->data[p] + (avctx->height - y - 1) * frame->linesize[p];
zstream->avail_out = avctx->width >> (p > 0);
ret = inflate(zstream, Z_SYNC_FLUSH);
if (ret != Z_OK && ret != Z_STREAM_END) {
av_log(avctx, AV_LOG_ERROR, "Inflate error: %d\n", ret);
return AVERROR_EXTERNAL;
}
}
}
} else if (type == MKTAG('H','U','F','Y')) {
GetBitContext *gb = &s->gb;
int first_symbol, symbol;
ret = init_get_bits8(gb, avpkt->data + 8, avpkt->size - 8);
if (ret < 0)
return ret;
skip_bits(gb, 24);
first_symbol = get_bits(gb, 8);
s->nb_symbols = get_bits(gb, 8) + 1;
symbol = first_symbol;
for (int i = 0; i < s->nb_symbols; symbol++) {
int prob;
if (get_bits_left(gb) < 4)
return AVERROR_INVALIDDATA;
if (get_bits1(gb)) {
prob = get_bits(gb, 12);
} else {
prob = get_bits(gb, 3);
}
if (prob) {
s->symb[i] = symbol;
s->prob[i] = prob;
i++;
}
}
ret = build_vlc(avctx, &s->vlc);
if (ret < 0)
return ret;
for (int p = 0; p < 3; p++) {
int width = avctx->width >> (p > 0);
ptrdiff_t stride = frame->linesize[p];
uint8_t *dst;
dst = frame->data[p] + (avctx->height - 1) * frame->linesize[p];
for (int y = 0; y < avctx->height; y++) {
if (get_bits_left(gb) < width)
return AVERROR_INVALIDDATA;
for (int x = 0; x < width; x++) {
int v = get_vlc2(gb, s->vlc.table, s->vlc.bits, 3);
if (v < 0)
return AVERROR_INVALIDDATA;
dst[x] = v;
}
dst -= stride;
}
}
} else {
return AVERROR_INVALIDDATA;
}
for (int p = 0; p < 3; p++) {
int left, lefttop;
int width = avctx->width >> (p > 0);
ptrdiff_t stride = frame->linesize[p];
uint8_t *dst;
dst = frame->data[p] + (avctx->height - 1) * frame->linesize[p];
s->llviddsp.add_left_pred(dst, dst, width, 0);
if (avctx->height > 1) {
dst -= stride;
lefttop = left = dst[0];
for (int y = 1; y < avctx->height; y++) {
s->llviddsp.add_median_pred(dst, dst + stride, dst, width, &left, &lefttop);
lefttop = left = dst[0];
dst -= stride;
}
}
}
frame->pict_type = AV_PICTURE_TYPE_I;
frame->key_frame = 1;
*got_frame = 1;
return avpkt->size;
}
static av_cold int decode_init(AVCodecContext *avctx)
{
MVHAContext *s = avctx->priv_data;
avctx->pix_fmt = AV_PIX_FMT_YUV422P;
ff_llviddsp_init(&s->llviddsp);
return ff_inflate_init(&s->zstream, avctx);
}
static av_cold int decode_close(AVCodecContext *avctx)
{
MVHAContext *s = avctx->priv_data;
ff_inflate_end(&s->zstream);
ff_free_vlc(&s->vlc);
return 0;
}
const FFCodec ff_mvha_decoder = {
.p.name = "mvha",
.p.long_name = NULL_IF_CONFIG_SMALL("MidiVid Archive Codec"),
.p.type = AVMEDIA_TYPE_VIDEO,
.p.id = AV_CODEC_ID_MVHA,
.priv_data_size = sizeof(MVHAContext),
.init = decode_init,
.close = decode_close,
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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