mirror of
https://github.com/FFmpeg/FFmpeg.git
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239 lines
8.3 KiB
C
239 lines
8.3 KiB
C
/*
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* Flash Screen Video decoder
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* Copyright (C) 2004 Alex Beregszaszi
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* Copyright (C) 2006 Benjamin Larsson
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*
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* This file is part of Libav.
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*
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* Libav 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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* Libav 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 Libav; 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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* Flash Screen Video decoder
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* @author Alex Beregszaszi
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* @author Benjamin Larsson
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*
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* A description of the bitstream format for Flash Screen Video version 1/2
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* is part of the SWF File Format Specification (version 10), which can be
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* downloaded from http://www.adobe.com/devnet/swf.html.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <zlib.h>
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#include "avcodec.h"
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#include "get_bits.h"
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typedef struct FlashSVContext {
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AVCodecContext *avctx;
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AVFrame frame;
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int image_width, image_height;
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int block_width, block_height;
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uint8_t *tmpblock;
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int block_size;
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z_stream zstream;
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} FlashSVContext;
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static av_cold int flashsv_decode_init(AVCodecContext *avctx)
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{
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FlashSVContext *s = avctx->priv_data;
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int zret; // Zlib return code
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s->avctx = avctx;
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s->zstream.zalloc = Z_NULL;
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s->zstream.zfree = Z_NULL;
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s->zstream.opaque = Z_NULL;
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zret = inflateInit(&s->zstream);
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if (zret != Z_OK) {
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av_log(avctx, AV_LOG_ERROR, "Inflate init error: %d\n", zret);
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return 1;
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}
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avctx->pix_fmt = PIX_FMT_BGR24;
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s->frame.data[0] = NULL;
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return 0;
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}
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static int flashsv_decode_frame(AVCodecContext *avctx, void *data,
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int *data_size, AVPacket *avpkt)
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{
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int buf_size = avpkt->size;
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FlashSVContext *s = avctx->priv_data;
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int h_blocks, v_blocks, h_part, v_part, i, j;
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GetBitContext gb;
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/* no supplementary picture */
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if (buf_size == 0)
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return 0;
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if (buf_size < 4)
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return -1;
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init_get_bits(&gb, avpkt->data, buf_size * 8);
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/* start to parse the bitstream */
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s->block_width = 16 * (get_bits(&gb, 4) + 1);
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s->image_width = get_bits(&gb, 12);
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s->block_height = 16 * (get_bits(&gb, 4) + 1);
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s->image_height = get_bits(&gb, 12);
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/* calculate number of blocks and size of border (partial) blocks */
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h_blocks = s->image_width / s->block_width;
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h_part = s->image_width % s->block_width;
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v_blocks = s->image_height / s->block_height;
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v_part = s->image_height % s->block_height;
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/* the block size could change between frames, make sure the buffer
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* is large enough, if not, get a larger one */
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if (s->block_size < s->block_width * s->block_height) {
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av_free(s->tmpblock);
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if ((s->tmpblock = av_malloc(3 * s->block_width * s->block_height)) == NULL) {
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av_log(avctx, AV_LOG_ERROR, "Can't allocate decompression buffer.\n");
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return AVERROR(ENOMEM);
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}
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}
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s->block_size = s->block_width * s->block_height;
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/* initialize the image size once */
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if (avctx->width == 0 && avctx->height == 0) {
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avctx->width = s->image_width;
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avctx->height = s->image_height;
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}
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/* check for changes of image width and image height */
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if (avctx->width != s->image_width || avctx->height != s->image_height) {
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av_log(avctx, AV_LOG_ERROR,
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"Frame width or height differs from first frames!\n");
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av_log(avctx, AV_LOG_ERROR, "fh = %d, fv %d vs ch = %d, cv = %d\n",
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avctx->height, avctx->width, s->image_height, s->image_width);
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return AVERROR_INVALIDDATA;
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}
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av_dlog(avctx, "image: %dx%d block: %dx%d num: %dx%d part: %dx%d\n",
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s->image_width, s->image_height, s->block_width, s->block_height,
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h_blocks, v_blocks, h_part, v_part);
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s->frame.reference = 3;
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s->frame.buffer_hints = FF_BUFFER_HINTS_VALID |
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FF_BUFFER_HINTS_PRESERVE |
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FF_BUFFER_HINTS_REUSABLE;
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if (avctx->reget_buffer(avctx, &s->frame) < 0) {
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av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
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return -1;
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}
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/* loop over all block columns */
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for (j = 0; j < v_blocks + (v_part ? 1 : 0); j++) {
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int y_pos = j * s->block_height; // vertical position in frame
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int cur_blk_height = (j < v_blocks) ? s->block_height : v_part;
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/* loop over all block rows */
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for (i = 0; i < h_blocks + (h_part ? 1 : 0); i++) {
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int x_pos = i * s->block_width; // horizontal position in frame
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int cur_blk_width = (i < h_blocks) ? s->block_width : h_part;
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/* get the size of the compressed zlib chunk */
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int size = get_bits(&gb, 16);
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if (8 * size > get_bits_left(&gb)) {
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avctx->release_buffer(avctx, &s->frame);
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s->frame.data[0] = NULL;
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return AVERROR_INVALIDDATA;
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}
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/* skip unchanged blocks, which have size 0 */
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if (size) {
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/* decompress block */
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uint8_t *line = s->tmpblock;
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int k;
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int ret = inflateReset(&s->zstream);
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if (ret != Z_OK) {
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av_log(avctx, AV_LOG_ERROR,
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"error in decompression (reset) of block %dx%d\n", i, j);
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/* return -1; */
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}
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s->zstream.next_in = avpkt->data + get_bits_count(&gb) / 8;
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s->zstream.avail_in = size;
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s->zstream.next_out = s->tmpblock;
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s->zstream.avail_out = s->block_size * 3;
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ret = inflate(&s->zstream, Z_FINISH);
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if (ret == Z_DATA_ERROR) {
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av_log(avctx, AV_LOG_ERROR, "Zlib resync occurred\n");
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inflateSync(&s->zstream);
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ret = inflate(&s->zstream, Z_FINISH);
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}
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if (ret != Z_OK && ret != Z_STREAM_END) {
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av_log(avctx, AV_LOG_ERROR,
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"error in decompression of block %dx%d: %d\n", i, j, ret);
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/* return -1; */
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}
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/* Flash Screen Video stores the image upside down, so copy
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* lines to destination in reverse order. */
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for (k = 1; k <= cur_blk_height; k++) {
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memcpy(s->frame.data[0] + x_pos * 3 +
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(s->image_height - y_pos - k) * s->frame.linesize[0],
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line, cur_blk_width * 3);
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/* advance source pointer to next line */
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line += cur_blk_width * 3;
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}
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skip_bits_long(&gb, 8 * size); /* skip the consumed bits */
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}
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}
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}
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*data_size = sizeof(AVFrame);
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*(AVFrame*)data = s->frame;
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if ((get_bits_count(&gb) / 8) != buf_size)
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av_log(avctx, AV_LOG_ERROR, "buffer not fully consumed (%d != %d)\n",
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buf_size, (get_bits_count(&gb) / 8));
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/* report that the buffer was completely consumed */
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return buf_size;
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}
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static av_cold int flashsv_decode_end(AVCodecContext *avctx)
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{
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FlashSVContext *s = avctx->priv_data;
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inflateEnd(&s->zstream);
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/* release the frame if needed */
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if (s->frame.data[0])
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avctx->release_buffer(avctx, &s->frame);
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/* free the tmpblock */
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av_free(s->tmpblock);
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return 0;
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}
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AVCodec ff_flashsv_decoder = {
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.name = "flashsv",
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.type = AVMEDIA_TYPE_VIDEO,
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.id = CODEC_ID_FLASHSV,
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.priv_data_size = sizeof(FlashSVContext),
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.init = flashsv_decode_init,
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.close = flashsv_decode_end,
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.decode = flashsv_decode_frame,
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.capabilities = CODEC_CAP_DR1,
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.pix_fmts = (const enum PixelFormat[]){PIX_FMT_BGR24, PIX_FMT_NONE},
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.long_name = NULL_IF_CONFIG_SMALL("Flash Screen Video v1"),
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};
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