diff options
Diffstat (limited to 'libavcodec/screenpresso.c')
| -rw-r--r-- | libavcodec/screenpresso.c | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/libavcodec/screenpresso.c b/libavcodec/screenpresso.c new file mode 100644 index 0000000000..e3150e9b2b --- /dev/null +++ b/libavcodec/screenpresso.c @@ -0,0 +1,186 @@ +/* + * 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: BGR24 + */ + +#include <stdint.h> +#include <string.h> +#include <zlib.h> + +#include "libavutil/imgutils.h" +#include "libavutil/internal.h" + +#include "avcodec.h" +#include "internal.h" + +typedef struct ScreenpressoContext { + AVFrame *current; + + /* zlib interation */ + 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); + + avctx->pix_fmt = AV_PIX_FMT_BGR24; + + 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; + int keyframe; + int ret; + + /* Size check */ + if (avpkt->size < 3) { + av_log(avctx, AV_LOG_ERROR, "Packet too small (%d)\n", avpkt->size); + return AVERROR_INVALIDDATA; + } + + /* Basic sanity check, but not really harmful */ + if ((avpkt->data[0] != 0x73 && avpkt->data[0] != 0x72) || + avpkt->data[1] != 8) { // bpp probably + av_log(avctx, AV_LOG_WARNING, "Unknown header 0x%02X%02X\n", + avpkt->data[0], avpkt->data[1]); + } + keyframe = (avpkt->data[0] == 0x73); + + /* Resize deflate buffer and frame on resolution change */ + if (ctx->inflated_size != avctx->width * avctx->height * 3) { + av_frame_unref(ctx->current); + ret = ff_get_buffer(avctx, ctx->current, AV_GET_BUFFER_FLAG_REF); + if (ret < 0) + return ret; + + /* If malloc fails, reset len to avoid preserving an invalid value */ + ctx->inflated_size = avctx->width * avctx->height * 3; + ret = av_reallocp(&ctx->inflated_buf, ctx->inflated_size); + if (ret < 0) { + ctx->inflated_size = 0; + return ret; + } + } + + /* Inflate the frame after the 2 byte header */ + ret = uncompress(ctx->inflated_buf, &ctx->inflated_size, + avpkt->data + 2, avpkt->size - 2); + if (ret) { + av_log(avctx, AV_LOG_ERROR, "Deflate error %d.\n", ret); + return AVERROR_UNKNOWN; + } + + /* 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, avctx->width * 3, + avctx->width * 3, 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, avctx->width * 3, + avctx->width * 3, 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, +}; |