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FFmpeg/libavcodec/screenpresso.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

199 lines
6.1 KiB
C

/*
* Screenpresso decoder
* Copyright (C) 2015 Vittorio Giovara <vittorio.giovara@gmail.com>
*
* 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
* Screenpresso decoder
*
* Fourcc: SPV1
*
* Screenpresso simply horizontally flips and then deflates frames,
* alternating full pictures and deltas. Deltas are related to the currently
* rebuilt frame (not the reference), and since there is no coordinate system
* they contain exactly as many pixel as the keyframe.
*
* Supports: BGR0, BGR24, RGB555
*/
#include <stdint.h>
#include <string.h>
#include <zlib.h>
#include "libavutil/imgutils.h"
#include "libavutil/internal.h"
#include "libavutil/mem.h"
#include "avcodec.h"
#include "internal.h"
typedef struct ScreenpressoContext {
AVFrame *current;
/* zlib interaction */
uint8_t *inflated_buf;
uLongf inflated_size;
} ScreenpressoContext;
static av_cold int screenpresso_close(AVCodecContext *avctx)
{
ScreenpressoContext *ctx = avctx->priv_data;
av_frame_free(&ctx->current);
av_freep(&ctx->inflated_buf);
return 0;
}
static av_cold int screenpresso_init(AVCodecContext *avctx)
{
ScreenpressoContext *ctx = avctx->priv_data;
/* These needs to be set to estimate uncompressed buffer */
int ret = av_image_check_size(avctx->width, avctx->height, 0, avctx);
if (ret < 0) {
av_log(avctx, AV_LOG_ERROR, "Invalid image size %dx%d.\n",
avctx->width, avctx->height);
return ret;
}
/* Allocate current frame */
ctx->current = av_frame_alloc();
if (!ctx->current)
return AVERROR(ENOMEM);
/* Allocate maximum size possible, a full RGBA frame */
ctx->inflated_size = avctx->width * avctx->height * 4;
ctx->inflated_buf = av_malloc(ctx->inflated_size);
if (!ctx->inflated_buf)
return AVERROR(ENOMEM);
return 0;
}
static void sum_delta_flipped(uint8_t *dst, int dst_linesize,
const uint8_t *src, int src_linesize,
int bytewidth, int height)
{
int i;
for (; height > 0; height--) {
const uint8_t *src1 = &src[(height - 1) * src_linesize];
for (i = 0; i < bytewidth; i++)
dst[i] += src1[i];
dst += dst_linesize;
}
}
static int screenpresso_decode_frame(AVCodecContext *avctx, void *data,
int *got_frame, AVPacket *avpkt)
{
ScreenpressoContext *ctx = avctx->priv_data;
AVFrame *frame = data;
uLongf length = ctx->inflated_size;
int keyframe, component_size, src_linesize;
int ret;
/* Size check */
if (avpkt->size < 3) {
av_log(avctx, AV_LOG_ERROR, "Packet too small (%d)\n", avpkt->size);
return AVERROR_INVALIDDATA;
}
/* Compression level (4 bits) and keyframe information (1 bit) */
av_log(avctx, AV_LOG_DEBUG, "Compression level %d\n", avpkt->data[0] >> 4);
keyframe = avpkt->data[0] & 1;
/* Pixel size */
component_size = ((avpkt->data[1] >> 2) & 0x03) + 1;
switch (component_size) {
case 2:
avctx->pix_fmt = AV_PIX_FMT_RGB555LE;
break;
case 3:
avctx->pix_fmt = AV_PIX_FMT_BGR24;
break;
case 4:
avctx->pix_fmt = AV_PIX_FMT_BGR0;
break;
default:
av_log(avctx, AV_LOG_ERROR, "Invalid bits per pixel value (%d)\n",
component_size);
return AVERROR_INVALIDDATA;
}
/* Inflate the frame after the 2 byte header */
ret = uncompress(ctx->inflated_buf, &length,
avpkt->data + 2, avpkt->size - 2);
if (ret) {
av_log(avctx, AV_LOG_ERROR, "Deflate error %d.\n", ret);
return AVERROR_UNKNOWN;
}
ret = ff_reget_buffer(avctx, ctx->current, 0);
if (ret < 0)
return ret;
/* Codec has aligned strides */
src_linesize = FFALIGN(avctx->width * component_size, 4);
/* When a keyframe is found, copy it (flipped) */
if (keyframe)
av_image_copy_plane(ctx->current->data[0] +
ctx->current->linesize[0] * (avctx->height - 1),
-1 * ctx->current->linesize[0],
ctx->inflated_buf, src_linesize,
avctx->width * component_size, avctx->height);
/* Otherwise sum the delta on top of the current frame */
else
sum_delta_flipped(ctx->current->data[0], ctx->current->linesize[0],
ctx->inflated_buf, src_linesize,
avctx->width * component_size, avctx->height);
/* Frame is ready to be output */
ret = av_frame_ref(frame, ctx->current);
if (ret < 0)
return ret;
/* Usual properties */
if (keyframe) {
frame->pict_type = AV_PICTURE_TYPE_I;
frame->key_frame = 1;
} else {
frame->pict_type = AV_PICTURE_TYPE_P;
}
*got_frame = 1;
return avpkt->size;
}
const AVCodec ff_screenpresso_decoder = {
.name = "screenpresso",
.long_name = NULL_IF_CONFIG_SMALL("Screenpresso"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_SCREENPRESSO,
.init = screenpresso_init,
.decode = screenpresso_decode_frame,
.close = screenpresso_close,
.priv_data_size = sizeof(ScreenpressoContext),
.capabilities = AV_CODEC_CAP_DR1,
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE |
FF_CODEC_CAP_INIT_CLEANUP,
};