/* * TechSmith Screen Codec 2 (aka Dora) decoder * Copyright (c) 2012 Konstantin Shishkov * * 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 * TechSmith Screen Codec 2 decoder */ #include <inttypes.h> #define BITSTREAM_READER_LE #include "avcodec.h" #include "get_bits.h" #include "bytestream.h" #include "internal.h" #include "tscc2data.h" typedef struct TSCC2Context { AVCodecContext *avctx; AVFrame *pic; int mb_width, mb_height; uint8_t *slice_quants; int quant[2]; int q[2][3]; GetBitContext gb; VLC dc_vlc, nc_vlc[NUM_VLC_SETS], ac_vlc[NUM_VLC_SETS]; int block[16]; } TSCC2Context; static av_cold void free_vlcs(TSCC2Context *c) { int i; ff_free_vlc(&c->dc_vlc); for (i = 0; i < NUM_VLC_SETS; i++) { ff_free_vlc(c->nc_vlc + i); ff_free_vlc(c->ac_vlc + i); } } static av_cold int init_vlcs(TSCC2Context *c) { int i, ret; ret = ff_init_vlc_sparse(&c->dc_vlc, 9, DC_VLC_COUNT, tscc2_dc_vlc_bits, 1, 1, tscc2_dc_vlc_codes, 2, 2, tscc2_dc_vlc_syms, 2, 2, INIT_VLC_LE); if (ret) return ret; for (i = 0; i < NUM_VLC_SETS; i++) { ret = ff_init_vlc_sparse(c->nc_vlc + i, 9, 16, tscc2_nc_vlc_bits[i], 1, 1, tscc2_nc_vlc_codes[i], 2, 2, tscc2_nc_vlc_syms, 1, 1, INIT_VLC_LE); if (ret) { free_vlcs(c); return ret; } ret = ff_init_vlc_sparse(c->ac_vlc + i, 9, tscc2_ac_vlc_sizes[i], tscc2_ac_vlc_bits[i], 1, 1, tscc2_ac_vlc_codes[i], 2, 2, tscc2_ac_vlc_syms[i], 2, 2, INIT_VLC_LE); if (ret) { free_vlcs(c); return ret; } } return 0; } #define DEQUANT(val, q) (((q) * (val) + 0x80) >> 8) #define DCT1D(d0, d1, d2, d3, s0, s1, s2, s3, OP) \ OP(d0, 5 * ((s0) + (s1) + (s2)) + 2 * (s3)); \ OP(d1, 5 * ((s0) - (s2) - (s3)) + 2 * (s1)); \ OP(d2, 5 * ((s0) - (s2) + (s3)) - 2 * (s1)); \ OP(d3, 5 * ((s0) - (s1) + (s2)) - 2 * (s3)); \ #define COL_OP(a, b) a = (b) #define ROW_OP(a, b) a = ((b) + 0x20) >> 6 static void tscc2_idct4_put(int *in, int q[3], uint8_t *dst, int stride) { int i; int tblk[4 * 4]; int t0, t1, t2, t3; for (i = 0; i < 4; i++) { t0 = DEQUANT(q[0 + (i & 1)], in[0 * 4 + i]); t1 = DEQUANT(q[1 + (i & 1)], in[1 * 4 + i]); t2 = DEQUANT(q[0 + (i & 1)], in[2 * 4 + i]); t3 = DEQUANT(q[1 + (i & 1)], in[3 * 4 + i]); DCT1D(tblk[0 * 4 + i], tblk[1 * 4 + i], tblk[2 * 4 + i], tblk[3 * 4 + i], t0, t1, t2, t3, COL_OP); } for (i = 0; i < 4; i++) { DCT1D(dst[0], dst[1], dst[2], dst[3], tblk[i * 4 + 0], tblk[i * 4 + 1], tblk[i * 4 + 2], tblk[i * 4 + 3], ROW_OP); dst += stride; } } static int tscc2_decode_mb(TSCC2Context *c, int *q, int vlc_set, uint8_t *dst, int stride, int plane) { GetBitContext *gb = &c->gb; int prev_dc, dc, nc, ac, bpos, val; int i, j, k, l; if (get_bits1(gb)) { if (get_bits1(gb)) { val = get_bits(gb, 8); for (i = 0; i < 8; i++, dst += stride) memset(dst, val, 16); } else { if (get_bits_left(gb) < 16 * 8 * 8) return AVERROR_INVALIDDATA; for (i = 0; i < 8; i++) { for (j = 0; j < 16; j++) dst[j] = get_bits(gb, 8); dst += stride; } } return 0; } prev_dc = 0; for (j = 0; j < 2; j++) { for (k = 0; k < 4; k++) { if (!(j | k)) { dc = get_bits(gb, 8); } else { dc = get_vlc2(gb, c->dc_vlc.table, 9, 2); if (dc == -1) return AVERROR_INVALIDDATA; if (dc == 0x100) dc = get_bits(gb, 8); } dc = (dc + prev_dc) & 0xFF; prev_dc = dc; c->block[0] = dc; nc = get_vlc2(gb, c->nc_vlc[vlc_set].table, 9, 1); if (nc == -1) return AVERROR_INVALIDDATA; bpos = 1; memset(c->block + 1, 0, 15 * sizeof(*c->block)); for (l = 0; l < nc; l++) { ac = get_vlc2(gb, c->ac_vlc[vlc_set].table, 9, 2); if (ac == -1) return AVERROR_INVALIDDATA; if (ac == 0x1000) ac = get_bits(gb, 12); bpos += ac & 0xF; if (bpos >= 16) return AVERROR_INVALIDDATA; val = sign_extend(ac >> 4, 8); c->block[tscc2_zigzag[bpos++]] = val; } tscc2_idct4_put(c->block, q, dst + k * 4, stride); } dst += 4 * stride; } return 0; } static int tscc2_decode_slice(TSCC2Context *c, int mb_y, const uint8_t *buf, int buf_size) { int i, mb_x, q, ret; int off; if ((ret = init_get_bits8(&c->gb, buf, buf_size)) < 0) return ret; for (mb_x = 0; mb_x < c->mb_width; mb_x++) { q = c->slice_quants[mb_x + c->mb_width * mb_y]; if (q == 0 || q == 3) // skip block continue; for (i = 0; i < 3; i++) { off = mb_x * 16 + mb_y * 8 * c->pic->linesize[i]; ret = tscc2_decode_mb(c, c->q[q - 1], c->quant[q - 1] - 2, c->pic->data[i] + off, c->pic->linesize[i], i); if (ret) return ret; } } return 0; } static int tscc2_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt) { const uint8_t *buf = avpkt->data; int buf_size = avpkt->size; TSCC2Context *c = avctx->priv_data; GetByteContext gb; uint32_t frame_type, size; int i, val, len, pos = 0; int num_mb = c->mb_width * c->mb_height; int ret; bytestream2_init(&gb, buf, buf_size); frame_type = bytestream2_get_byte(&gb); if (frame_type > 1) { av_log(avctx, AV_LOG_ERROR, "Incorrect frame type %"PRIu32"\n", frame_type); return AVERROR_INVALIDDATA; } if ((ret = ff_reget_buffer(avctx, c->pic)) < 0) { return ret; } if (frame_type == 0) { *got_frame = 1; if ((ret = av_frame_ref(data, c->pic)) < 0) return ret; return buf_size; } if (bytestream2_get_bytes_left(&gb) < 4) { av_log(avctx, AV_LOG_ERROR, "Frame is too short\n"); return AVERROR_INVALIDDATA; } c->quant[0] = bytestream2_get_byte(&gb); c->quant[1] = bytestream2_get_byte(&gb); if (c->quant[0] < 2 || c->quant[0] > NUM_VLC_SETS + 1 || c->quant[1] < 2 || c->quant[1] > NUM_VLC_SETS + 1) { av_log(avctx, AV_LOG_ERROR, "Invalid quantisers %d / %d\n", c->quant[0], c->quant[1]); return AVERROR_INVALIDDATA; } for (i = 0; i < 3; i++) { c->q[0][i] = tscc2_quants[c->quant[0] - 2][i]; c->q[1][i] = tscc2_quants[c->quant[1] - 2][i]; } bytestream2_skip(&gb, 1); size = bytestream2_get_le32(&gb); if (size > bytestream2_get_bytes_left(&gb)) { av_log(avctx, AV_LOG_ERROR, "Slice properties chunk is too large\n"); return AVERROR_INVALIDDATA; } for (i = 0; i < size; i++) { val = bytestream2_get_byte(&gb); len = val & 0x3F; val >>= 6; if (pos + len > num_mb) { av_log(avctx, AV_LOG_ERROR, "Too many slice properties\n"); return AVERROR_INVALIDDATA; } memset(c->slice_quants + pos, val, len); pos += len; } if (pos < num_mb) { av_log(avctx, AV_LOG_ERROR, "Too few slice properties (%d / %d)\n", pos, num_mb); return AVERROR_INVALIDDATA; } for (i = 0; i < c->mb_height; i++) { size = bytestream2_peek_byte(&gb); if (size & 1) { size = bytestream2_get_byte(&gb) - 1; } else { size = bytestream2_get_le32(&gb) >> 1; } if (!size) { int skip_row = 1, j, off = i * c->mb_width; for (j = 0; j < c->mb_width; j++) { if (c->slice_quants[off + j] == 1 || c->slice_quants[off + j] == 2) { skip_row = 0; break; } } if (!skip_row) { av_log(avctx, AV_LOG_ERROR, "Non-skip row with zero size\n"); return AVERROR_INVALIDDATA; } } if (bytestream2_get_bytes_left(&gb) < size) { av_log(avctx, AV_LOG_ERROR, "Invalid slice size (%"PRIu32"/%u)\n", size, bytestream2_get_bytes_left(&gb)); return AVERROR_INVALIDDATA; } ret = tscc2_decode_slice(c, i, buf + bytestream2_tell(&gb), size); if (ret) { av_log(avctx, AV_LOG_ERROR, "Error decoding slice %d\n", i); return ret; } bytestream2_skip(&gb, size); } *got_frame = 1; if ((ret = av_frame_ref(data, c->pic)) < 0) return ret; /* always report that the buffer was completely consumed */ return buf_size; } static av_cold int tscc2_decode_end(AVCodecContext *avctx) { TSCC2Context * const c = avctx->priv_data; av_frame_free(&c->pic); av_freep(&c->slice_quants); free_vlcs(c); return 0; } static av_cold int tscc2_decode_init(AVCodecContext *avctx) { TSCC2Context * const c = avctx->priv_data; int ret; c->avctx = avctx; avctx->pix_fmt = AV_PIX_FMT_YUV444P; if ((ret = init_vlcs(c)) < 0) { av_log(avctx, AV_LOG_ERROR, "Cannot initialise VLCs\n"); return ret; } c->mb_width = FFALIGN(avctx->width, 16) >> 4; c->mb_height = FFALIGN(avctx->height, 8) >> 3; c->slice_quants = av_malloc(c->mb_width * c->mb_height); if (!c->slice_quants) { av_log(avctx, AV_LOG_ERROR, "Cannot allocate slice information\n"); free_vlcs(c); return AVERROR(ENOMEM); } c->pic = av_frame_alloc(); if (!c->pic) { tscc2_decode_end(avctx); return AVERROR(ENOMEM); } return 0; } AVCodec ff_tscc2_decoder = { .name = "tscc2", .long_name = NULL_IF_CONFIG_SMALL("TechSmith Screen Codec 2"), .type = AVMEDIA_TYPE_VIDEO, .id = AV_CODEC_ID_TSCC2, .priv_data_size = sizeof(TSCC2Context), .init = tscc2_decode_init, .close = tscc2_decode_end, .decode = tscc2_decode_frame, .capabilities = CODEC_CAP_DR1, };