static int kmvc_decode_inter_8x8(KmvcContext * ctx, const uint8_t * src, int src_size, int w, int h) { BitBuf bb; int res, val; int i, j; int bx, by; int l0x, l1x, l0y, l1y; int mx, my; const uint8_t *src_end = src + src_size; kmvc_init_getbits(bb, src); for (by = 0; by < h; by += 8) for (bx = 0; bx < w; bx += 8) { kmvc_getbit(bb, src, src_end, res); if (!res) { kmvc_getbit(bb, src, src_end, res); if (!res) { // fill whole 8x8 block if (src >= src_end) { av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n"); return AVERROR_INVALIDDATA; } val = *src++; for (i = 0; i < 64; i++) BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val; } else { // copy block from previous frame for (i = 0; i < 64; i++) BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = BLK(ctx->prev, bx + (i & 0x7), by + (i >> 3)); } } else { // handle four 4x4 subblocks for (i = 0; i < 4; i++) { l0x = bx + (i & 1) * 4; l0y = by + (i & 2) * 2; kmvc_getbit(bb, src, src_end, res); if (!res) { kmvc_getbit(bb, src, src_end, res); if (!res) { // fill whole 4x4 block if (src >= src_end) { av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n"); return AVERROR_INVALIDDATA; } val = *src++; for (j = 0; j < 16; j++) BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val; } else { // copy block if (src >= src_end) { av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n"); return AVERROR_INVALIDDATA; } val = *src++; mx = (val & 0xF) - 8; my = (val >> 4) - 8; for (j = 0; j < 16; j++) BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = BLK(ctx->prev, l0x + (j & 3) + mx, l0y + (j >> 2) + my); } } else { // descend to 2x2 sub-sub-blocks for (j = 0; j < 4; j++) { l1x = l0x + (j & 1) * 2; l1y = l0y + (j & 2); kmvc_getbit(bb, src, src_end, res); if (!res) { kmvc_getbit(bb, src, src_end, res); if (!res) { // fill whole 2x2 block if (src >= src_end) { av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n"); return AVERROR_INVALIDDATA; } val = *src++; BLK(ctx->cur, l1x, l1y) = val; BLK(ctx->cur, l1x + 1, l1y) = val; BLK(ctx->cur, l1x, l1y + 1) = val; BLK(ctx->cur, l1x + 1, l1y + 1) = val; } else { // copy block if (src >= src_end) { av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n"); return AVERROR_INVALIDDATA; } val = *src++; mx = (val & 0xF) - 8; my = (val >> 4) - 8; BLK(ctx->cur, l1x, l1y) = BLK(ctx->prev, l1x + mx, l1y + my); BLK(ctx->cur, l1x + 1, l1y) = BLK(ctx->prev, l1x + 1 + mx, l1y + my); BLK(ctx->cur, l1x, l1y + 1) = BLK(ctx->prev, l1x + mx, l1y + 1 + my); BLK(ctx->cur, l1x + 1, l1y + 1) = BLK(ctx->prev, l1x + 1 + mx, l1y + 1 + my); } } else { // read values for block BLK(ctx->cur, l1x, l1y) = *src++; BLK(ctx->cur, l1x + 1, l1y) = *src++; BLK(ctx->cur, l1x, l1y + 1) = *src++; BLK(ctx->cur, l1x + 1, l1y + 1) = *src++; } } } } } } return 0; }