/* * Screenpresso decoder * Copyright (C) 2015 Vittorio Giovara <vittorio.giovara@gmail.com> * * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; 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: BGRA, 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--) { for (i = 0; i < bytewidth; i++) dst[i] += src[(height - 1) * src_linesize + 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_BGRA; 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); 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 0; } 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, };