/* * FM Screen Capture Codec decoder * * Copyright (c) 2017 Paul B Mahol * * 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 */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include "avcodec.h" #include "bytestream.h" #include "internal.h" #define BLOCK_HEIGHT 112u #define BLOCK_WIDTH 84u typedef struct InterBlock { int w, h; int size; int xor; } InterBlock; typedef struct FMVCContext { GetByteContext gb; PutByteContext pb; uint8_t *buffer; size_t buffer_size; uint8_t *pbuffer; size_t pbuffer_size; ptrdiff_t stride; int bpp; int yb, xb; InterBlock *blocks; unsigned nb_blocks; } FMVCContext; static int decode_type2(GetByteContext *gb, PutByteContext *pb) { unsigned repeat = 0, first = 1, opcode = 0; int i, len, pos; while (bytestream2_get_bytes_left(gb) > 0) { GetByteContext gbc; while (bytestream2_get_bytes_left(gb) > 0) { if (first) { first = 0; if (bytestream2_peek_byte(gb) > 17) { len = bytestream2_get_byte(gb) - 17; if (len < 4) { do { bytestream2_put_byte(pb, bytestream2_get_byte(gb)); --len; } while (len); opcode = bytestream2_peek_byte(gb); continue; } else { do { bytestream2_put_byte(pb, bytestream2_get_byte(gb)); --len; } while (len); opcode = bytestream2_peek_byte(gb); if (opcode < 0x10) { bytestream2_skip(gb, 1); pos = - (opcode >> 2) - 4 * bytestream2_get_byte(gb) - 2049; bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start); bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos, SEEK_SET); bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); len = opcode & 3; if (!len) { repeat = 1; } else { do { bytestream2_put_byte(pb, bytestream2_get_byte(gb)); --len; } while (len); opcode = bytestream2_peek_byte(gb); } continue; } } repeat = 0; } repeat = 1; } if (repeat) { repeat = 0; opcode = bytestream2_peek_byte(gb); if (opcode < 0x10) { bytestream2_skip(gb, 1); if (!opcode) { if (!bytestream2_peek_byte(gb)) { do { bytestream2_skip(gb, 1); opcode += 255; } while (!bytestream2_peek_byte(gb) && bytestream2_get_bytes_left(gb) > 0); } opcode += bytestream2_get_byte(gb) + 15; } bytestream2_put_le32(pb, bytestream2_get_le32(gb)); for (i = opcode - 1; i > 0; --i) bytestream2_put_byte(pb, bytestream2_get_byte(gb)); opcode = bytestream2_peek_byte(gb); if (opcode < 0x10) { bytestream2_skip(gb, 1); pos = - (opcode >> 2) - 4 * bytestream2_get_byte(gb) - 2049; bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start); bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos, SEEK_SET); bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); len = opcode & 3; if (!len) { repeat = 1; } else { do { bytestream2_put_byte(pb, bytestream2_get_byte(gb)); --len; } while (len); opcode = bytestream2_peek_byte(gb); } continue; } } } if (opcode >= 0x40) { bytestream2_skip(gb, 1); pos = - ((opcode >> 2) & 7) - 1 - 8 * bytestream2_get_byte(gb); len = (opcode >> 5) - 1; bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start); bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos, SEEK_SET); bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); do { bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); --len; } while (len); len = opcode & 3; if (!len) { repeat = 1; } else { do { bytestream2_put_byte(pb, bytestream2_get_byte(gb)); --len; } while (len); opcode = bytestream2_peek_byte(gb); } continue; } else if (opcode < 0x20) { break; } len = opcode & 0x1F; bytestream2_skip(gb, 1); if (!len) { if (!bytestream2_peek_byte(gb)) { do { bytestream2_skip(gb, 1); len += 255; } while (!bytestream2_peek_byte(gb) && bytestream2_get_bytes_left(gb) > 0); } len += bytestream2_get_byte(gb) + 31; } i = bytestream2_get_le16(gb); pos = - (i >> 2) - 1; bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start); bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos, SEEK_SET); if (len < 6 || bytestream2_tell_p(pb) - bytestream2_tell(&gbc) < 4) { bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); do { bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); --len; } while (len); } else { bytestream2_put_le32(pb, bytestream2_get_le32(&gbc)); for (len = len - 2; len; --len) bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); } len = i & 3; if (!len) { repeat = 1; } else { do { bytestream2_put_byte(pb, bytestream2_get_byte(gb)); --len; } while (len); opcode = bytestream2_peek_byte(gb); } } bytestream2_skip(gb, 1); if (opcode < 0x10) { pos = -(opcode >> 2) - 1 - 4 * bytestream2_get_byte(gb); bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start); bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos, SEEK_SET); bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); len = opcode & 3; if (!len) { repeat = 1; } else { do { bytestream2_put_byte(pb, bytestream2_get_byte(gb)); --len; } while (len); opcode = bytestream2_peek_byte(gb); } continue; } len = opcode & 7; if (!len) { if (!bytestream2_peek_byte(gb)) { do { bytestream2_skip(gb, 1); len += 255; } while (!bytestream2_peek_byte(gb) && bytestream2_get_bytes_left(gb) > 0); } len += bytestream2_get_byte(gb) + 7; } i = bytestream2_get_le16(gb); pos = bytestream2_tell_p(pb) - 2048 * (opcode & 8); pos = pos - (i >> 2); if (pos == bytestream2_tell_p(pb)) break; pos = pos - 0x4000; bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start); bytestream2_seek(&gbc, pos, SEEK_SET); if (len < 6 || bytestream2_tell_p(pb) - bytestream2_tell(&gbc) < 4) { bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); do { bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); --len; } while (len); } else { bytestream2_put_le32(pb, bytestream2_get_le32(&gbc)); for (len = len - 2; len; --len) bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); } len = i & 3; if (!len) { repeat = 1; } else { do { bytestream2_put_byte(pb, bytestream2_get_byte(gb)); --len; } while (len); opcode = bytestream2_peek_byte(gb); } } return 0; } static int decode_type1(GetByteContext *gb, PutByteContext *pb) { unsigned opcode = 0, len; int high = 0; int i, pos; while (bytestream2_get_bytes_left(gb) > 0) { GetByteContext gbc; while (bytestream2_get_bytes_left(gb) > 0) { while (bytestream2_get_bytes_left(gb) > 0) { opcode = bytestream2_get_byte(gb); high = opcode >= 0x20; if (high) break; if (opcode) break; opcode = bytestream2_get_byte(gb); if (opcode < 0xF8) { opcode += 32; break; } i = opcode - 0xF8; if (i) { len = 256; do { len *= 2; --i; } while (i); } else { len = 280; } do { bytestream2_put_le32(pb, bytestream2_get_le32(gb)); bytestream2_put_le32(pb, bytestream2_get_le32(gb)); len -= 8; } while (len && bytestream2_get_bytes_left(gb) > 0); } if (!high) { do { bytestream2_put_byte(pb, bytestream2_get_byte(gb)); --opcode; } while (opcode && bytestream2_get_bytes_left(gb) > 0); while (bytestream2_get_bytes_left(gb) > 0) { GetByteContext gbc; opcode = bytestream2_get_byte(gb); if (opcode >= 0x20) break; bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start); pos = -(opcode | 32 * bytestream2_get_byte(gb)) - 1; bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos, SEEK_SET); bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); bytestream2_put_byte(pb, bytestream2_get_byte(gb)); } } high = 0; if (opcode < 0x40) break; bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start); pos = (-((opcode & 0x1F) | 32 * bytestream2_get_byte(gb)) - 1); bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos, SEEK_SET); bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); len = (opcode >> 5) - 1; do { bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); --len; } while (len && bytestream2_get_bytes_left(&gbc) > 0); } len = opcode & 0x1F; if (!len) { if (!bytestream2_peek_byte(gb)) { do { bytestream2_skip(gb, 1); len += 255; } while (!bytestream2_peek_byte(gb) && bytestream2_get_bytes_left(gb) > 0); } len += bytestream2_get_byte(gb) + 31; } pos = -bytestream2_get_byte(gb); bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start); bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos - (bytestream2_get_byte(gb) << 8), SEEK_SET); if (bytestream2_tell_p(pb) == bytestream2_tell(&gbc)) break; if (len < 5 || bytestream2_tell_p(pb) - bytestream2_tell(&gbc) < 4) { bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); } else { bytestream2_put_le32(pb, bytestream2_get_le32(&gbc)); len--; } do { bytestream2_put_byte(pb, bytestream2_get_byte(&gbc)); len--; } while (len && bytestream2_get_bytes_left(&gbc) > 0); } return 0; } static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt) { FMVCContext *s = avctx->priv_data; GetByteContext *gb = &s->gb; PutByteContext *pb = &s->pb; AVFrame *frame = data; int ret, y, x; if (avpkt->size < 8) return AVERROR_INVALIDDATA; if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) return ret; bytestream2_init(gb, avpkt->data, avpkt->size); bytestream2_skip(gb, 2); frame->key_frame = !!bytestream2_get_le16(gb); frame->pict_type = frame->key_frame ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P; if (frame->key_frame) { const uint8_t *src; unsigned type, size; uint8_t *dst; type = bytestream2_get_le16(gb); size = bytestream2_get_le16(gb); if (size > bytestream2_get_bytes_left(gb)) return AVERROR_INVALIDDATA; bytestream2_init_writer(pb, s->buffer, s->buffer_size); if (type == 1) { decode_type1(gb, pb); } else if (type == 2){ decode_type2(gb, pb); } else { avpriv_report_missing_feature(avctx, "Compression type %d", type); return AVERROR_PATCHWELCOME; } src = s->buffer; dst = frame->data[0] + (avctx->height - 1) * frame->linesize[0]; for (y = 0; y < avctx->height; y++) { memcpy(dst, src, avctx->width * s->bpp); dst -= frame->linesize[0]; src += s->stride * 4; if (bytestream2_tell_p(pb) < y*s->stride * 4) break; } } else { unsigned block, nb_blocks; int type, k, l; uint8_t *ssrc, *ddst; const uint32_t *src; uint32_t *dst; for (block = 0; block < s->nb_blocks; block++) s->blocks[block].xor = 0; nb_blocks = bytestream2_get_le16(gb); if (nb_blocks > s->nb_blocks) return AVERROR_INVALIDDATA; bytestream2_init_writer(pb, s->pbuffer, s->pbuffer_size); type = bytestream2_get_le16(gb); for (block = 0; block < nb_blocks; block++) { unsigned size, offset; int start = 0; offset = bytestream2_get_le16(gb); if (offset >= s->nb_blocks) return AVERROR_INVALIDDATA; size = bytestream2_get_le16(gb); if (size > bytestream2_get_bytes_left(gb)) return AVERROR_INVALIDDATA; start = bytestream2_tell_p(pb); if (type == 1) { decode_type1(gb, pb); } else if (type == 2){ decode_type2(gb, pb); } else { avpriv_report_missing_feature(avctx, "Compression type %d", type); return AVERROR_PATCHWELCOME; } if (s->blocks[offset].size * 4 != bytestream2_tell_p(pb) - start) return AVERROR_INVALIDDATA; s->blocks[offset].xor = 1; } src = (const uint32_t *)s->pbuffer; dst = (uint32_t *)s->buffer; for (block = 0, y = 0; y < s->yb; y++) { int block_h = s->blocks[block].h; uint32_t *rect = dst; for (x = 0; x < s->xb; x++) { int block_w = s->blocks[block].w; uint32_t *row = dst; block_h = s->blocks[block].h; if (s->blocks[block].xor) { for (k = 0; k < block_h; k++) { uint32_t *column = dst; for (l = 0; l < block_w; l++) *dst++ ^= *src++; dst = &column[s->stride]; } } dst = &row[block_w]; ++block; } dst = &rect[block_h * s->stride]; } ssrc = s->buffer; ddst = frame->data[0] + (avctx->height - 1) * frame->linesize[0]; for (y = 0; y < avctx->height; y++) { memcpy(ddst, ssrc, avctx->width * s->bpp); ddst -= frame->linesize[0]; ssrc += s->stride * 4; } } *got_frame = 1; return avpkt->size; } static av_cold int decode_init(AVCodecContext *avctx) { FMVCContext *s = avctx->priv_data; int i, j, m, block = 0, h = BLOCK_HEIGHT, w = BLOCK_WIDTH; switch (avctx->bits_per_coded_sample) { case 16: avctx->pix_fmt = AV_PIX_FMT_RGB555LE; break; case 24: avctx->pix_fmt = AV_PIX_FMT_BGR24; break; case 32: avctx->pix_fmt = AV_PIX_FMT_BGRA; break; default: av_log(avctx, AV_LOG_ERROR, "Unsupported bitdepth %i\n", avctx->bits_per_coded_sample); return AVERROR_INVALIDDATA; } s->stride = (avctx->width * avctx->bits_per_coded_sample + 31) / 32; s->xb = s->stride / BLOCK_WIDTH; m = s->stride % BLOCK_WIDTH; if (m) { if (m < 37) { w = m + BLOCK_WIDTH; } else { w = m; s->xb++; } } s->yb = avctx->height / BLOCK_HEIGHT; m = avctx->height % BLOCK_HEIGHT; if (m) { if (m < 49) { h = m + BLOCK_HEIGHT; } else { h = m; s->yb++; } } s->nb_blocks = s->xb * s->yb; if (!s->nb_blocks) return AVERROR_INVALIDDATA; s->blocks = av_calloc(s->nb_blocks, sizeof(*s->blocks)); if (!s->blocks) return AVERROR(ENOMEM); for (i = 0; i < s->yb; i++) { for (j = 0; j < s->xb; j++) { if (i != (s->yb - 1) || j != (s->xb - 1)) { if (i == s->yb - 1) { s->blocks[block].w = BLOCK_WIDTH; s->blocks[block].h = h; s->blocks[block].size = BLOCK_WIDTH * h; } else if (j == s->xb - 1) { s->blocks[block].w = w; s->blocks[block].h = BLOCK_HEIGHT; s->blocks[block].size = BLOCK_HEIGHT * w; } else { s->blocks[block].w = BLOCK_WIDTH; s->blocks[block].h = BLOCK_HEIGHT; s->blocks[block].size = BLOCK_WIDTH * BLOCK_HEIGHT; } } else { s->blocks[block].w = w; s->blocks[block].h = h; s->blocks[block].size = w * h; } block++; } } s->bpp = avctx->bits_per_coded_sample >> 3; s->buffer_size = avctx->width * avctx->height * 4; s->pbuffer_size = avctx->width * avctx->height * 4; s->buffer = av_mallocz(s->buffer_size); s->pbuffer = av_mallocz(s->pbuffer_size); if (!s->buffer || !s->pbuffer) return AVERROR(ENOMEM); return 0; } static av_cold int decode_close(AVCodecContext *avctx) { FMVCContext *s = avctx->priv_data; av_freep(&s->buffer); av_freep(&s->pbuffer); av_freep(&s->blocks); return 0; } const AVCodec ff_fmvc_decoder = { .name = "fmvc", .long_name = NULL_IF_CONFIG_SMALL("FM Screen Capture Codec"), .type = AVMEDIA_TYPE_VIDEO, .id = AV_CODEC_ID_FMVC, .priv_data_size = sizeof(FMVCContext), .init = decode_init, .close = decode_close, .decode = decode_frame, .capabilities = AV_CODEC_CAP_DR1, .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP, };