mirror of
https://git.videolan.org/git/ffmpeg.git
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198 lines
6.0 KiB
C
198 lines
6.0 KiB
C
/*
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* Screenpresso decoder
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* Copyright (C) 2015 Vittorio Giovara <vittorio.giovara@gmail.com>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* Screenpresso decoder
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*
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* Fourcc: SPV1
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*
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* Screenpresso simply horizontally flips and then deflates frames,
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* alternating full pictures and deltas. Deltas are related to the currently
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* rebuilt frame (not the reference), and since there is no coordinate system
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* they contain exactly as many pixel as the keyframe.
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*
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* Supports: BGR0, BGR24, RGB555
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*/
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#include <stdint.h>
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#include <string.h>
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#include <zlib.h>
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#include "libavutil/imgutils.h"
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#include "libavutil/internal.h"
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#include "libavutil/mem.h"
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#include "avcodec.h"
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#include "internal.h"
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typedef struct ScreenpressoContext {
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AVFrame *current;
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/* zlib interaction */
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uint8_t *inflated_buf;
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uLongf inflated_size;
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} ScreenpressoContext;
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static av_cold int screenpresso_close(AVCodecContext *avctx)
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{
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ScreenpressoContext *ctx = avctx->priv_data;
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av_frame_free(&ctx->current);
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av_freep(&ctx->inflated_buf);
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return 0;
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}
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static av_cold int screenpresso_init(AVCodecContext *avctx)
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{
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ScreenpressoContext *ctx = avctx->priv_data;
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/* These needs to be set to estimate uncompressed buffer */
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int ret = av_image_check_size(avctx->width, avctx->height, 0, avctx);
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if (ret < 0) {
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av_log(avctx, AV_LOG_ERROR, "Invalid image size %dx%d.\n",
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avctx->width, avctx->height);
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return ret;
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}
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/* Allocate current frame */
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ctx->current = av_frame_alloc();
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if (!ctx->current)
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return AVERROR(ENOMEM);
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/* Allocate maximum size possible, a full RGBA frame */
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ctx->inflated_size = avctx->width * avctx->height * 4;
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ctx->inflated_buf = av_malloc(ctx->inflated_size);
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if (!ctx->inflated_buf)
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return AVERROR(ENOMEM);
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return 0;
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}
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static void sum_delta_flipped(uint8_t *dst, int dst_linesize,
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const uint8_t *src, int src_linesize,
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int bytewidth, int height)
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{
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int i;
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for (; height > 0; height--) {
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for (i = 0; i < bytewidth; i++)
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dst[i] += src[(height - 1) * src_linesize + i];
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dst += dst_linesize;
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}
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}
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static int screenpresso_decode_frame(AVCodecContext *avctx, void *data,
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int *got_frame, AVPacket *avpkt)
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{
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ScreenpressoContext *ctx = avctx->priv_data;
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AVFrame *frame = data;
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uLongf length = ctx->inflated_size;
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int keyframe, component_size, src_linesize;
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int ret;
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/* Size check */
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if (avpkt->size < 3) {
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av_log(avctx, AV_LOG_ERROR, "Packet too small (%d)\n", avpkt->size);
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return AVERROR_INVALIDDATA;
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}
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/* Compression level (4 bits) and keyframe information (1 bit) */
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av_log(avctx, AV_LOG_DEBUG, "Compression level %d\n", avpkt->data[0] >> 4);
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keyframe = avpkt->data[0] & 1;
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/* Pixel size */
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component_size = ((avpkt->data[1] >> 2) & 0x03) + 1;
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switch (component_size) {
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case 2:
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avctx->pix_fmt = AV_PIX_FMT_RGB555LE;
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break;
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case 3:
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avctx->pix_fmt = AV_PIX_FMT_BGR24;
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break;
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case 4:
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avctx->pix_fmt = AV_PIX_FMT_BGR0;
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break;
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default:
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av_log(avctx, AV_LOG_ERROR, "Invalid bits per pixel value (%d)\n",
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component_size);
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return AVERROR_INVALIDDATA;
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}
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/* Inflate the frame after the 2 byte header */
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ret = uncompress(ctx->inflated_buf, &length,
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avpkt->data + 2, avpkt->size - 2);
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if (ret) {
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av_log(avctx, AV_LOG_ERROR, "Deflate error %d.\n", ret);
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return AVERROR_UNKNOWN;
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}
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ret = ff_reget_buffer(avctx, ctx->current);
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if (ret < 0)
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return ret;
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/* Codec has aligned strides */
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src_linesize = FFALIGN(avctx->width * component_size, 4);
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/* When a keyframe is found, copy it (flipped) */
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if (keyframe)
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av_image_copy_plane(ctx->current->data[0] +
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ctx->current->linesize[0] * (avctx->height - 1),
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-1 * ctx->current->linesize[0],
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ctx->inflated_buf, src_linesize,
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avctx->width * component_size, avctx->height);
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/* Otherwise sum the delta on top of the current frame */
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else
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sum_delta_flipped(ctx->current->data[0], ctx->current->linesize[0],
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ctx->inflated_buf, src_linesize,
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avctx->width * component_size, avctx->height);
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/* Frame is ready to be output */
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ret = av_frame_ref(frame, ctx->current);
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if (ret < 0)
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return ret;
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/* Usual properties */
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if (keyframe) {
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frame->pict_type = AV_PICTURE_TYPE_I;
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frame->key_frame = 1;
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} else {
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frame->pict_type = AV_PICTURE_TYPE_P;
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}
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*got_frame = 1;
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return 0;
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}
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AVCodec ff_screenpresso_decoder = {
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.name = "screenpresso",
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.long_name = NULL_IF_CONFIG_SMALL("Screenpresso"),
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.type = AVMEDIA_TYPE_VIDEO,
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.id = AV_CODEC_ID_SCREENPRESSO,
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.init = screenpresso_init,
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.decode = screenpresso_decode_frame,
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.close = screenpresso_close,
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.priv_data_size = sizeof(ScreenpressoContext),
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.capabilities = AV_CODEC_CAP_DR1,
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.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE |
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FF_CODEC_CAP_INIT_CLEANUP,
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};
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