/*
* Microsoft Video-1 Encoder
* Copyright (c) 2009 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
* Microsoft Video-1 encoder
*/
#include "avcodec.h"
#include "bytestream.h"
#include "libavutil/lfg.h"
#include "elbg.h"
#include "libavutil/imgutils.h"
/**
* Encoder context
*/
typedef struct Msvideo1EncContext {
AVCodecContext *avctx;
AVFrame pic;
AVLFG rnd;
uint8_t *prev;
int block[16*3];
int block2[16*3];
int codebook[8*3];
int codebook2[8*3];
int output[16*3];
int output2[16*3];
int avg[3];
int bestpos;
int keyint;
} Msvideo1EncContext;
enum MSV1Mode{
MODE_SKIP = 0,
MODE_FILL,
MODE_2COL,
MODE_8COL,
};
#define SKIP_PREFIX 0x8400
#define SKIPS_MAX 0x0FFF
#define MKRGB555(in, off) ((in[off] << 10) | (in[off + 1] << 5) | (in[off + 2]))
static const int remap[16] = { 0, 1, 4, 5, 2, 3, 6, 7, 8, 9, 12, 13, 10, 11, 14, 15 };
static int encode_frame(AVCodecContext *avctx, uint8_t *buf, int buf_size, void *data)
{
Msvideo1EncContext * const c = avctx->priv_data;
AVFrame *pict = data;
AVFrame * const p = &c->pic;
uint16_t *src;
uint8_t *prevptr;
uint8_t *dst = buf;
int keyframe = 1;
int no_skips = 1;
int i, j, k, x, y;
int skips = 0;
*p = *pict;
if(!c->prev)
c->prev = av_malloc(avctx->width * 3 * (avctx->height + 3));
prevptr = c->prev + avctx->width * 3 * (FFALIGN(avctx->height, 4) - 1);
src = (uint16_t*)(p->data[0] + p->linesize[0]*(FFALIGN(avctx->height, 4) - 1));
if(c->keyint >= avctx->keyint_min)
keyframe = 1;
p->quality = 24;
for(y = 0; y < avctx->height; y += 4){
for(x = 0; x < avctx->width; x += 4){
int bestmode = MODE_SKIP;
int bestscore = INT_MAX;
int flags = 0;
int score;
for(j = 0; j < 4; j++){
for(i = 0; i < 4; i++){
uint16_t val = src[x + i - j*p->linesize[0]/2];
for(k = 0; k < 3; k++){
c->block[(i + j*4)*3 + k] =
c->block2[remap[i + j*4]*3 + k] = (val >> (10-k*5)) & 0x1F;
}
}
}
if(!keyframe){
bestscore = 0;
for(j = 0; j < 4; j++){
for(i = 0; i < 4*3; i++){
int t = prevptr[x*3 + i + j*p->linesize[0]] - c->block[i + j*4*3];
bestscore += t*t;
}
}
bestscore /= p->quality;
}
// try to find optimal value to fill whole 4x4 block
score = 0;
ff_init_elbg(c->block, 3, 16, c->avg, 1, 1, c->output, &c->rnd);
ff_do_elbg (c->block, 3, 16, c->avg, 1, 1, c->output, &c->rnd);
if(c->avg[0] == 1) // red component = 1 will be written as skip code
c->avg[0] = 0;
for(j = 0; j < 4; j++){
for(i = 0; i < 4; i++){
for(k = 0; k < 3; k++){
int t = c->avg[k] - c->block[(i+j*4)*3+k];
score += t*t;
}
}
}
score /= p->quality;
score += 2;
if(score < bestscore){
bestscore = score;
bestmode = MODE_FILL;
}
// search for optimal filling of 2-color block
score = 0;
ff_init_elbg(c->block, 3, 16, c->codebook, 2, 1, c->output, &c->rnd);
ff_do_elbg (c->block, 3, 16, c->codebook, 2, 1, c->output, &c->rnd);
// last output value should be always 1, swap codebooks if needed
if(!c->output[15]){
for(i = 0; i < 3; i++)
FFSWAP(uint8_t, c->codebook[i], c->codebook[i+3]);
for(i = 0; i < 16; i++)
c->output[i] ^= 1;
}
for(j = 0; j < 4; j++){
for(i = 0; i < 4; i++){
for(k = 0; k < 3; k++){
int t = c->codebook[c->output[i+j*4]*3 + k] - c->block[i*3+k+j*4*3];
score += t*t;
}
}
}
score /= p->quality;
score += 6;
if(score < bestscore){
bestscore = score;
bestmode = MODE_2COL;
}
// search for optimal filling of 2-color 2x2 subblocks
score = 0;
for(i = 0; i < 4; i++){
ff_init_elbg(c->block2 + i*4*3, 3, 4, c->codebook2 + i*2*3, 2, 1, c->output2 + i*4, &c->rnd);
ff_do_elbg (c->block2 + i*4*3, 3, 4, c->codebook2 + i*2*3, 2, 1, c->output2 + i*4, &c->rnd);
}
// last value should be always 1, swap codebooks if needed
if(!c->output2[15]){
for(i = 0; i < 3; i++)
FFSWAP(uint8_t, c->codebook2[i+18], c->codebook2[i+21]);
for(i = 12; i < 16; i++)
c->output2[i] ^= 1;
}
for(j = 0; j < 4; j++){
for(i = 0; i < 4; i++){
for(k = 0; k < 3; k++){
int t = c->codebook2[(c->output2[remap[i+j*4]] + (i&2) + (j&2)*2)*3+k] - c->block[i*3+k + j*4*3];
score += t*t;
}
}
}
score /= p->quality;
score += 18;
if(score < bestscore){
bestscore = score;
bestmode = MODE_8COL;
}
if(bestmode == MODE_SKIP){
skips++;
no_skips = 0;
}
if((bestmode != MODE_SKIP && skips) || skips == SKIPS_MAX){
bytestream_put_le16(&dst, skips | SKIP_PREFIX);
skips = 0;
}
switch(bestmode){
case MODE_FILL:
bytestream_put_le16(&dst, MKRGB555(c->avg,0) | 0x8000);
for(j = 0; j < 4; j++)
for(i = 0; i < 4; i++)
for(k = 0; k < 3; k++)
prevptr[i*3 + k - j*3*avctx->width] = c->avg[k];
break;
case MODE_2COL:
for(j = 0; j < 4; j++){
for(i = 0; i < 4; i++){
flags |= (c->output[i + j*4]^1) << (i + j*4);
for(k = 0; k < 3; k++)
prevptr[i*3 + k - j*3*avctx->width] = c->codebook[c->output[i + j*4]*3 + k];
}
}
bytestream_put_le16(&dst, flags);
bytestream_put_le16(&dst, MKRGB555(c->codebook, 0));
bytestream_put_le16(&dst, MKRGB555(c->codebook, 3));
break;
case MODE_8COL:
for(j = 0; j < 4; j++){
for(i = 0; i < 4; i++){
flags |= (c->output2[remap[i + j*4]]^1) << (i + j*4);
for(k = 0; k < 3; k++)
prevptr[i*3 + k - j*3*avctx->width] = c->codebook2[(c->output2[remap[i+j*4]] + (i&2) + (j&2)*2)*3 + k];
}
}
bytestream_put_le16(&dst, flags);
bytestream_put_le16(&dst, MKRGB555(c->codebook2, 0) | 0x8000);
for(i = 3; i < 24; i += 3)
bytestream_put_le16(&dst, MKRGB555(c->codebook2, i));
break;
}
}
src -= p->linesize[0] << 1;
prevptr -= avctx->width * 3 * 4;
}
if(skips)
bytestream_put_le16(&dst, skips | SKIP_PREFIX);
//EOF
bytestream_put_byte(&dst, 0);
bytestream_put_byte(&dst, 0);
if(no_skips)
keyframe = 1;
if(keyframe)
c->keyint = 0;
else
c->keyint++;
p->pict_type= keyframe ? FF_I_TYPE : FF_P_TYPE;
p->key_frame= keyframe;
return dst - buf;
}
/**
* init encoder
*/
static av_cold int encode_init(AVCodecContext *avctx)
{
Msvideo1EncContext * const c = avctx->priv_data;
c->avctx = avctx;
if (av_image_check_size(avctx->width, avctx->height, 0, avctx) < 0) {
return -1;
}
if((avctx->width&3) || (avctx->height&3)){
av_log(avctx, AV_LOG_ERROR, "width and height must be multiplies of 4\n");
return -1;
}
avcodec_get_frame_defaults(&c->pic);
avctx->coded_frame = (AVFrame*)&c->pic;
c->keyint = avctx->keyint_min;
av_lfg_init(&c->rnd, 1);
return 0;
}
/**
* Uninit encoder
*/
static av_cold int encode_end(AVCodecContext *avctx)
{
Msvideo1EncContext * const c = avctx->priv_data;
av_freep(&c->prev);
return 0;
}
AVCodec ff_msvideo1_encoder = {
"msvideo1",
AVMEDIA_TYPE_VIDEO,
CODEC_ID_MSVIDEO1,
sizeof(Msvideo1EncContext),
encode_init,
encode_frame,
encode_end,
.pix_fmts = (const enum PixelFormat[]){PIX_FMT_RGB555, PIX_FMT_NONE},
.long_name = NULL_IF_CONFIG_SMALL("Microsoft Video-1"),
};