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ffmpeg/libavcodec/qtrleenc.c

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/*
* Quicktime Animation (RLE) Video Encoder
* Copyright (C) 2007 Clemens Fruhwirth
* Copyright (C) 2007 Alexis Ballier
*
* This file is based on flashsvenc.c.
*
* 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 "libavutil/imgutils.h"
#include "avcodec.h"
#include "bytestream.h"
/** Maximum RLE code for bulk copy */
#define MAX_RLE_BULK 127
/** Maximum RLE code for repeat */
#define MAX_RLE_REPEAT 128
/** Maximum RLE code for skip */
#define MAX_RLE_SKIP 254
typedef struct QtrleEncContext {
AVCodecContext *avctx;
AVFrame frame;
int pixel_size;
AVPicture previous_frame;
unsigned int max_buf_size;
int logical_width;
/**
* This array will contain at ith position the value of the best RLE code
* if the line started at pixel i
* There can be 3 values :
* skip (0) : skip as much as possible pixels because they are equal to the
* previous frame ones
* repeat (<-1) : repeat that pixel -rle_code times, still as much as
* possible
* copy (>0) : copy the raw next rle_code pixels */
signed char *rlecode_table;
/**
* This array will contain the length of the best rle encoding of the line
* starting at ith pixel */
int *length_table;
/**
* Will contain at ith position the number of consecutive pixels equal to the previous
* frame starting from pixel i */
uint8_t* skip_table;
} QtrleEncContext;
static av_cold int qtrle_encode_init(AVCodecContext *avctx)
{
QtrleEncContext *s = avctx->priv_data;
if (av_image_check_size(avctx->width, avctx->height, 0, avctx) < 0) {
return -1;
}
s->avctx=avctx;
s->logical_width=avctx->width;
switch (avctx->pix_fmt) {
case PIX_FMT_GRAY8:
s->logical_width = avctx->width / 4;
s->pixel_size = 4;
break;
case PIX_FMT_RGB555BE:
s->pixel_size = 2;
break;
case PIX_FMT_RGB24:
s->pixel_size = 3;
break;
case PIX_FMT_ARGB:
s->pixel_size = 4;
break;
default:
av_log(avctx, AV_LOG_ERROR, "Unsupported colorspace.\n");
break;
}
avctx->bits_per_coded_sample = avctx->pix_fmt == PIX_FMT_GRAY8 ? 40 : s->pixel_size*8;
s->rlecode_table = av_mallocz(s->logical_width);
s->skip_table = av_mallocz(s->logical_width);
s->length_table = av_mallocz((s->logical_width + 1)*sizeof(int));
if (!s->skip_table || !s->length_table || !s->rlecode_table) {
av_log(avctx, AV_LOG_ERROR, "Error allocating memory.\n");
return -1;
}
if (avpicture_alloc(&s->previous_frame, avctx->pix_fmt, avctx->width, avctx->height) < 0) {
av_log(avctx, AV_LOG_ERROR, "Error allocating picture\n");
return -1;
}
s->max_buf_size = s->logical_width*s->avctx->height*s->pixel_size /* image base material */
+ 15 /* header + footer */
+ s->avctx->height*2 /* skip code+rle end */
+ s->logical_width/MAX_RLE_BULK + 1 /* rle codes */;
avctx->coded_frame = &s->frame;
return 0;
}
/**
* Compute the best RLE sequence for a line
*/
static void qtrle_encode_line(QtrleEncContext *s, AVFrame *p, int line, uint8_t **buf)
{
int width=s->logical_width;
int i;
signed char rlecode;
/* We will use it to compute the best bulk copy sequence */
unsigned int bulkcount;
/* This will be the number of pixels equal to the preivous frame one's
* starting from the ith pixel */
unsigned int skipcount;
/* This will be the number of consecutive equal pixels in the current
* frame, starting from the ith one also */
unsigned int av_uninit(repeatcount);
/* The cost of the three different possibilities */
int total_bulk_cost;
int total_skip_cost;
int total_repeat_cost;
int temp_cost;
int j;
uint8_t *this_line = p-> data[0] + line*p-> linesize[0] +
(width - 1)*s->pixel_size;
uint8_t *prev_line = s->previous_frame.data[0] + line*s->previous_frame.linesize[0] +
(width - 1)*s->pixel_size;
s->length_table[width] = 0;
skipcount = 0;
for (i = width - 1; i >= 0; i--) {
if (!s->frame.key_frame && !memcmp(this_line, prev_line, s->pixel_size))
skipcount = FFMIN(skipcount + 1, MAX_RLE_SKIP);
else
skipcount = 0;
total_skip_cost = s->length_table[i + skipcount] + 2;
s->skip_table[i] = skipcount;
if (i < width - 1 && !memcmp(this_line, this_line + s->pixel_size, s->pixel_size))
repeatcount = FFMIN(repeatcount + 1, MAX_RLE_REPEAT);
else
repeatcount = 1;
total_repeat_cost = s->length_table[i + repeatcount] + 1 + s->pixel_size;
/* skip code is free for the first pixel, it costs one byte for repeat and bulk copy
* so let's make it aware */
if (i == 0) {
total_skip_cost--;
total_repeat_cost++;
}
if (repeatcount > 1 && (skipcount == 0 || total_repeat_cost < total_skip_cost)) {
/* repeat is the best */
s->length_table[i] = total_repeat_cost;
s->rlecode_table[i] = -repeatcount;
}
else if (skipcount > 0) {
/* skip is the best choice here */
s->length_table[i] = total_skip_cost;
s->rlecode_table[i] = 0;
}
else {
/* We cannot do neither skip nor repeat
* thus we search for the best bulk copy to do */
int limit = FFMIN(width - i, MAX_RLE_BULK);
temp_cost = 1 + s->pixel_size + !i;
total_bulk_cost = INT_MAX;
for (j = 1; j <= limit; j++) {
if (s->length_table[i + j] + temp_cost < total_bulk_cost) {
/* We have found a better bulk copy ... */
total_bulk_cost = s->length_table[i + j] + temp_cost;
bulkcount = j;
}
temp_cost += s->pixel_size;
}
s->length_table[i] = total_bulk_cost;
s->rlecode_table[i] = bulkcount;
}
this_line -= s->pixel_size;
prev_line -= s->pixel_size;
}
/* Good ! Now we have the best sequence for this line, let's ouput it */
/* We do a special case for the first pixel so that we avoid testing it in
* the whole loop */
i=0;
this_line = p-> data[0] + line*p->linesize[0];
if (s->rlecode_table[0] == 0) {
bytestream_put_byte(buf, s->skip_table[0] + 1);
i += s->skip_table[0];
}
else bytestream_put_byte(buf, 1);
while (i < width) {
rlecode = s->rlecode_table[i];
bytestream_put_byte(buf, rlecode);
if (rlecode == 0) {
/* Write a skip sequence */
bytestream_put_byte(buf, s->skip_table[i] + 1);
i += s->skip_table[i];
}
else if (rlecode > 0) {
/* bulk copy */
if (s->avctx->pix_fmt == PIX_FMT_GRAY8) {
int j;
// QT grayscale colorspace has 0=white and 255=black, we will
// ignore the palette that is included in the AVFrame because
// PIX_FMT_GRAY8 has defined color mapping
for (j = 0; j < rlecode*s->pixel_size; ++j)
bytestream_put_byte(buf, *(this_line + i*s->pixel_size + j) ^ 0xff);
} else {
bytestream_put_buffer(buf, this_line + i*s->pixel_size, rlecode*s->pixel_size);
}
i += rlecode;
}
else {
/* repeat the bits */
if (s->avctx->pix_fmt == PIX_FMT_GRAY8) {
int j;
// QT grayscale colorspace has 0=white and 255=black, ...
for (j = 0; j < s->pixel_size; ++j)
bytestream_put_byte(buf, *(this_line + i*s->pixel_size + j) ^ 0xff);
} else {
bytestream_put_buffer(buf, this_line + i*s->pixel_size, s->pixel_size);
}
i -= rlecode;
}
}
bytestream_put_byte(buf, -1); // end RLE line
}
/** Encode frame including header */
static int encode_frame(QtrleEncContext *s, AVFrame *p, uint8_t *buf)
{
int i;
int start_line = 0;
int end_line = s->avctx->height;
uint8_t *orig_buf = buf;
if (!s->frame.key_frame) {
unsigned line_size = s->logical_width * s->pixel_size;
for (start_line = 0; start_line < s->avctx->height; start_line++)
if (memcmp(p->data[0] + start_line*p->linesize[0],
s->previous_frame.data[0] + start_line*s->previous_frame.linesize[0],
line_size))
break;
for (end_line=s->avctx->height; end_line > start_line; end_line--)
if (memcmp(p->data[0] + (end_line - 1)*p->linesize[0],
s->previous_frame.data[0] + (end_line - 1)*s->previous_frame.linesize[0],
line_size))
break;
}
bytestream_put_be32(&buf, 0); // CHUNK SIZE, patched later
if ((start_line == 0 && end_line == s->avctx->height) || start_line == s->avctx->height)
bytestream_put_be16(&buf, 0); // header
else {
bytestream_put_be16(&buf, 8); // header
bytestream_put_be16(&buf, start_line); // starting line
bytestream_put_be16(&buf, 0); // unknown
bytestream_put_be16(&buf, end_line - start_line); // lines to update
bytestream_put_be16(&buf, 0); // unknown
}
for (i = start_line; i < end_line; i++)
qtrle_encode_line(s, p, i, &buf);
bytestream_put_byte(&buf, 0); // zero skip code = frame finished
AV_WB32(orig_buf, buf - orig_buf); // patch the chunk size
return buf - orig_buf;
}
static int qtrle_encode_frame(AVCodecContext *avctx, uint8_t *buf, int buf_size, void *data)
{
QtrleEncContext * const s = avctx->priv_data;
AVFrame *pict = data;
AVFrame * const p = &s->frame;
int chunksize;
*p = *pict;
if (buf_size < s->max_buf_size) {
/* Upper bound check for compressed data */
av_log(avctx, AV_LOG_ERROR, "buf_size %d < %d\n", buf_size, s->max_buf_size);
return -1;
}
if (avctx->gop_size == 0 || (s->avctx->frame_number % avctx->gop_size) == 0) {
/* I-Frame */
p->pict_type = AV_PICTURE_TYPE_I;
p->key_frame = 1;
} else {
/* P-Frame */
p->pict_type = AV_PICTURE_TYPE_P;
p->key_frame = 0;
}
chunksize = encode_frame(s, pict, buf);
/* save the current frame */
av_picture_copy(&s->previous_frame, (AVPicture *)p, avctx->pix_fmt, avctx->width, avctx->height);
return chunksize;
}
static av_cold int qtrle_encode_end(AVCodecContext *avctx)
{
QtrleEncContext *s = avctx->priv_data;
avpicture_free(&s->previous_frame);
av_free(s->rlecode_table);
av_free(s->length_table);
av_free(s->skip_table);
return 0;
}
AVCodec ff_qtrle_encoder = {
.name = "qtrle",
.type = AVMEDIA_TYPE_VIDEO,
.id = CODEC_ID_QTRLE,
.priv_data_size = sizeof(QtrleEncContext),
.init = qtrle_encode_init,
.encode = qtrle_encode_frame,
.close = qtrle_encode_end,
.pix_fmts = (const enum PixelFormat[]){PIX_FMT_RGB24, PIX_FMT_RGB555BE, PIX_FMT_ARGB, PIX_FMT_GRAY8, PIX_FMT_NONE},
.long_name = NULL_IF_CONFIG_SMALL("QuickTime Animation (RLE) video"),
};
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