static int bfi_decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt) { const uint8_t *buf = avpkt->data, *buf_end = avpkt->data + avpkt->size; int buf_size = avpkt->size; BFIContext *bfi = avctx->priv_data; uint8_t *dst = bfi->dst; uint8_t *src, *dst_offset, colour1, colour2; uint8_t *frame_end = bfi->dst + avctx->width * avctx->height; uint32_t *pal; int i, j, height = avctx->height; if (bfi->frame.data[0]) avctx->release_buffer(avctx, &bfi->frame); bfi->frame.reference = 1; if (avctx->get_buffer(avctx, &bfi->frame) < 0) { av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); return -1; } /* Set frame parameters and palette, if necessary */ if (!avctx->frame_number) { bfi->frame.pict_type = AV_PICTURE_TYPE_I; bfi->frame.key_frame = 1; /* Setting the palette */ if (avctx->extradata_size > 768) { av_log(NULL, AV_LOG_ERROR, "Palette is too large.\n"); return -1; } pal = (uint32_t *)bfi->frame.data[1]; for (i = 0; i < avctx->extradata_size / 3; i++) { int shift = 16; *pal = 0; for (j = 0; j < 3; j++, shift -= 8) *pal += ((avctx->extradata[i * 3 + j] << 2) | (avctx->extradata[i * 3 + j] >> 4)) << shift; pal++; } bfi->frame.palette_has_changed = 1; } else { bfi->frame.pict_type = AV_PICTURE_TYPE_P; bfi->frame.key_frame = 0; } buf += 4; // Unpacked size, not required. while (dst != frame_end) { static const uint8_t lentab[4] = { 0, 2, 0, 1 }; unsigned int byte = *buf++, av_uninit(offset); unsigned int code = byte >> 6; unsigned int length = byte & ~0xC0; if (buf >= buf_end) { av_log(avctx, AV_LOG_ERROR, "Input resolution larger than actual frame.\n"); return -1; } /* Get length and offset(if required) */ if (length == 0) { if (code == 1) { length = bytestream_get_byte(&buf); offset = bytestream_get_le16(&buf); } else { length = bytestream_get_le16(&buf); if (code == 2 && length == 0) break; } } else { if (code == 1) offset = bytestream_get_byte(&buf); } /* Do boundary check */ if (dst + (length << lentab[code]) > frame_end) break; switch (code) { case 0: //Normal Chain if (length >= buf_end - buf) { av_log(avctx, AV_LOG_ERROR, "Frame larger than buffer.\n"); return -1; } bytestream_get_buffer(&buf, dst, length); dst += length; break; case 1: //Back Chain dst_offset = dst - offset; length *= 4; //Convert dwords to bytes. if (dst_offset < bfi->dst) break; while (length--) *dst++ = *dst_offset++; break; case 2: //Skip Chain dst += length; break; case 3: //Fill Chain colour1 = bytestream_get_byte(&buf); colour2 = bytestream_get_byte(&buf); while (length--) { *dst++ = colour1; *dst++ = colour2; } break; } } src = bfi->dst; dst = bfi->frame.data[0]; while (height--) { memcpy(dst, src, avctx->width); src += avctx->width; dst += bfi->frame.linesize[0]; } *data_size = sizeof(AVFrame); *(AVFrame *)data = bfi->frame; return buf_size; }