LCOV - code coverage report
Current view: top level - libavcodec - screenpresso.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 64 75 85.3 %
Date: 2017-12-17 23:02:56 Functions: 4 4 100.0 %

          Line data    Source code
       1             : /*
       2             :  * Screenpresso decoder
       3             :  * Copyright (C) 2015 Vittorio Giovara <vittorio.giovara@gmail.com>
       4             :  *
       5             :  * This file is part of FFmpeg.
       6             :  *
       7             :  * FFmpeg is free software; you can redistribute it and/or
       8             :  * modify it under the terms of the GNU Lesser General Public
       9             :  * License as published by the Free Software Foundation; either
      10             :  * version 2.1 of the License, or (at your option) any later version.
      11             :  *
      12             :  * FFmpeg is distributed in the hope that it will be useful,
      13             :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      14             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      15             :  * Lesser General Public License for more details.
      16             :  *
      17             :  * You should have received a copy of the GNU Lesser General Public
      18             :  * License along with FFmpeg; if not, write to the Free Software
      19             :  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
      20             :  */
      21             : 
      22             : /**
      23             :  * @file
      24             :  * Screenpresso decoder
      25             :  *
      26             :  * Fourcc: SPV1
      27             :  *
      28             :  * Screenpresso simply horizontally flips and then deflates frames,
      29             :  * alternating full pictures and deltas. Deltas are related to the currently
      30             :  * rebuilt frame (not the reference), and since there is no coordinate system
      31             :  * they contain exactly as many pixel as the keyframe.
      32             :  *
      33             :  * Supports: BGR0, BGR24, RGB555
      34             :  */
      35             : 
      36             : #include <stdint.h>
      37             : #include <string.h>
      38             : #include <zlib.h>
      39             : 
      40             : #include "libavutil/imgutils.h"
      41             : #include "libavutil/internal.h"
      42             : #include "libavutil/mem.h"
      43             : 
      44             : #include "avcodec.h"
      45             : #include "internal.h"
      46             : 
      47             : typedef struct ScreenpressoContext {
      48             :     AVFrame *current;
      49             : 
      50             :     /* zlib interaction */
      51             :     uint8_t *inflated_buf;
      52             :     uLongf inflated_size;
      53             : } ScreenpressoContext;
      54             : 
      55           6 : static av_cold int screenpresso_close(AVCodecContext *avctx)
      56             : {
      57           6 :     ScreenpressoContext *ctx = avctx->priv_data;
      58             : 
      59           6 :     av_frame_free(&ctx->current);
      60           6 :     av_freep(&ctx->inflated_buf);
      61             : 
      62           6 :     return 0;
      63             : }
      64             : 
      65           6 : static av_cold int screenpresso_init(AVCodecContext *avctx)
      66             : {
      67           6 :     ScreenpressoContext *ctx = avctx->priv_data;
      68             : 
      69             :     /* These needs to be set to estimate uncompressed buffer */
      70           6 :     int ret = av_image_check_size(avctx->width, avctx->height, 0, avctx);
      71           6 :     if (ret < 0) {
      72           0 :         av_log(avctx, AV_LOG_ERROR, "Invalid image size %dx%d.\n",
      73             :                avctx->width, avctx->height);
      74           0 :         return ret;
      75             :     }
      76             : 
      77             :     /* Allocate current frame */
      78           6 :     ctx->current = av_frame_alloc();
      79           6 :     if (!ctx->current)
      80           0 :         return AVERROR(ENOMEM);
      81             : 
      82             :     /* Allocate maximum size possible, a full RGBA frame */
      83           6 :     ctx->inflated_size = avctx->width * avctx->height * 4;
      84           6 :     ctx->inflated_buf  = av_malloc(ctx->inflated_size);
      85           6 :     if (!ctx->inflated_buf)
      86           0 :         return AVERROR(ENOMEM);
      87             : 
      88           6 :     return 0;
      89             : }
      90             : 
      91          13 : static void sum_delta_flipped(uint8_t       *dst, int dst_linesize,
      92             :                               const uint8_t *src, int src_linesize,
      93             :                               int bytewidth, int height)
      94             : {
      95             :     int i;
      96        3493 :     for (; height > 0; height--) {
      97     4073880 :         for (i = 0; i < bytewidth; i++)
      98     4070400 :             dst[i] += src[(height - 1) * src_linesize + i];
      99        3480 :         dst += dst_linesize;
     100             :     }
     101          13 : }
     102             : 
     103          21 : static int screenpresso_decode_frame(AVCodecContext *avctx, void *data,
     104             :                                      int *got_frame, AVPacket *avpkt)
     105             : {
     106          21 :     ScreenpressoContext *ctx = avctx->priv_data;
     107          21 :     AVFrame *frame = data;
     108          21 :     uLongf length = ctx->inflated_size;
     109             :     int keyframe, component_size, src_linesize;
     110             :     int ret;
     111             : 
     112             :     /* Size check */
     113          21 :     if (avpkt->size < 3) {
     114           0 :         av_log(avctx, AV_LOG_ERROR, "Packet too small (%d)\n", avpkt->size);
     115           0 :         return AVERROR_INVALIDDATA;
     116             :     }
     117             : 
     118             :     /* Compression level (4 bits) and keyframe information (1 bit) */
     119          21 :     av_log(avctx, AV_LOG_DEBUG, "Compression level %d\n", avpkt->data[0] >> 4);
     120          21 :     keyframe = avpkt->data[0] & 1;
     121             : 
     122             :     /* Pixel size */
     123          21 :     component_size = ((avpkt->data[1] >> 2) & 0x03) + 1;
     124          21 :     switch (component_size) {
     125          10 :     case 2:
     126          10 :         avctx->pix_fmt = AV_PIX_FMT_RGB555LE;
     127          10 :         break;
     128           5 :     case 3:
     129           5 :         avctx->pix_fmt = AV_PIX_FMT_BGR24;
     130           5 :         break;
     131           6 :     case 4:
     132           6 :         avctx->pix_fmt = AV_PIX_FMT_BGR0;
     133           6 :         break;
     134           0 :     default:
     135           0 :         av_log(avctx, AV_LOG_ERROR, "Invalid bits per pixel value (%d)\n",
     136             :                component_size);
     137           0 :         return AVERROR_INVALIDDATA;
     138             :     }
     139             : 
     140             :     /* Inflate the frame after the 2 byte header */
     141          42 :     ret = uncompress(ctx->inflated_buf, &length,
     142          42 :                      avpkt->data + 2, avpkt->size - 2);
     143          21 :     if (ret) {
     144           2 :         av_log(avctx, AV_LOG_ERROR, "Deflate error %d.\n", ret);
     145           2 :         return AVERROR_UNKNOWN;
     146             :     }
     147             : 
     148          19 :     ret = ff_reget_buffer(avctx, ctx->current);
     149          19 :     if (ret < 0)
     150           0 :         return ret;
     151             : 
     152             :     /* Codec has aligned strides */
     153          19 :     src_linesize = FFALIGN(avctx->width * component_size, 4);
     154             : 
     155             :     /* When a keyframe is found, copy it (flipped) */
     156          19 :     if (keyframe)
     157          24 :         av_image_copy_plane(ctx->current->data[0] +
     158           6 :                             ctx->current->linesize[0] * (avctx->height - 1),
     159           6 :                             -1 * ctx->current->linesize[0],
     160           6 :                             ctx->inflated_buf, src_linesize,
     161           6 :                             avctx->width * component_size, avctx->height);
     162             :     /* Otherwise sum the delta on top of the current frame */
     163             :     else
     164          39 :         sum_delta_flipped(ctx->current->data[0], ctx->current->linesize[0],
     165          13 :                           ctx->inflated_buf, src_linesize,
     166          13 :                           avctx->width * component_size, avctx->height);
     167             : 
     168             :     /* Frame is ready to be output */
     169          19 :     ret = av_frame_ref(frame, ctx->current);
     170          19 :     if (ret < 0)
     171           0 :         return ret;
     172             : 
     173             :     /* Usual properties */
     174          19 :     if (keyframe) {
     175           6 :         frame->pict_type = AV_PICTURE_TYPE_I;
     176           6 :         frame->key_frame = 1;
     177             :     } else {
     178          13 :         frame->pict_type = AV_PICTURE_TYPE_P;
     179             :     }
     180          19 :     *got_frame = 1;
     181             : 
     182          19 :     return avpkt->size;
     183             : }
     184             : 
     185             : AVCodec ff_screenpresso_decoder = {
     186             :     .name           = "screenpresso",
     187             :     .long_name      = NULL_IF_CONFIG_SMALL("Screenpresso"),
     188             :     .type           = AVMEDIA_TYPE_VIDEO,
     189             :     .id             = AV_CODEC_ID_SCREENPRESSO,
     190             :     .init           = screenpresso_init,
     191             :     .decode         = screenpresso_decode_frame,
     192             :     .close          = screenpresso_close,
     193             :     .priv_data_size = sizeof(ScreenpressoContext),
     194             :     .capabilities   = AV_CODEC_CAP_DR1,
     195             :     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE |
     196             :                       FF_CODEC_CAP_INIT_CLEANUP,
     197             : };

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