static int bethsoftvid_decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt) { BethsoftvidContext * vid = avctx->priv_data; char block_type; uint8_t * dst; uint8_t * frame_end; int remaining = avctx->width; // number of bytes remaining on a line const int wrap_to_next_line = vid->frame.linesize[0] - avctx->width; int code; int yoffset; if (avctx->reget_buffer(avctx, &vid->frame)) { av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n"); return -1; } bytestream2_init(&vid->g, avpkt->data, avpkt->size); dst = vid->frame.data[0]; frame_end = vid->frame.data[0] + vid->frame.linesize[0] * avctx->height; switch(block_type = bytestream2_get_byte(&vid->g)){ case PALETTE_BLOCK: { int ret; *data_size = 0; if ((ret = set_palette(vid)) < 0) { av_log(avctx, AV_LOG_ERROR, "error reading palette\n"); return ret; } return bytestream2_tell(&vid->g); } case VIDEO_YOFF_P_FRAME: yoffset = bytestream2_get_le16(&vid->g); if(yoffset >= avctx->height) return -1; dst += vid->frame.linesize[0] * yoffset; } // main code while((code = bytestream2_get_byte(&vid->g))){ int length = code & 0x7f; // copy any bytes starting at the current position, and ending at the frame width while(length > remaining){ if(code < 0x80) bytestream2_get_buffer(&vid->g, dst, remaining); else if(block_type == VIDEO_I_FRAME) memset(dst, bytestream2_peek_byte(&vid->g), remaining); length -= remaining; // decrement the number of bytes to be copied dst += remaining + wrap_to_next_line; // skip over extra bytes at end of frame remaining = avctx->width; if(dst == frame_end) goto end; } // copy any remaining bytes after / if line overflows if(code < 0x80) bytestream2_get_buffer(&vid->g, dst, length); else if(block_type == VIDEO_I_FRAME) memset(dst, bytestream2_get_byte(&vid->g), length); remaining -= length; dst += length; } end: *data_size = sizeof(AVFrame); *(AVFrame*)data = vid->frame; return avpkt->size; }