diff --git a/C/zstdmt/brotli-mt_compress.c b/C/zstdmt/brotli-mt_compress.c
index 736821ae..d8dad2b4 100644
--- a/C/zstdmt/brotli-mt_compress.c
+++ b/C/zstdmt/brotli-mt_compress.c
@@ -383,7 +383,7 @@ static size_t st_compress(void *arg)
 	  /* 0, or not specified by user; could be chosen by compressor. */
 	  uint32_t lgwin = 24 /* DEFAULT_LGWIN */;
 	  /* Use file size to limit lgwin. */
-	  if (ctx->unpackSize >= 0) {
+	  if (ctx->unpackSize >= 0 && ctx->unpackSize != (uint64_t)(int64_t)-1) {
 	    lgwin = BROTLI_MIN_WINDOW_BITS;
 	    while (BROTLI_MAX_BACKWARD_LIMIT(lgwin) <
 	           (uint64_t)ctx->unpackSize) {
@@ -393,7 +393,7 @@ static size_t st_compress(void *arg)
 	  }
 	  BrotliEncoderSetParameter(state, BROTLI_PARAM_LGWIN, lgwin);
 	}
-	if (ctx->unpackSize > 0) {
+	if (ctx->unpackSize > 0 && ctx->unpackSize != (uint64_t)(int64_t)-1) {
 		uint32_t size_hint = ctx->unpackSize < (1 << 30) ?
 	    (uint32_t)ctx->unpackSize : (1u << 30);
 		BrotliEncoderSetParameter(state, BROTLI_PARAM_SIZE_HINT, size_hint);
diff --git a/CPP/7zip/Compress/BrotliEncoder.cpp b/CPP/7zip/Compress/BrotliEncoder.cpp
index b44fc582..4343a848 100644
--- a/CPP/7zip/Compress/BrotliEncoder.cpp
+++ b/CPP/7zip/Compress/BrotliEncoder.cpp
@@ -15,7 +15,8 @@ CEncoder::CEncoder():
   _numThreads(NWindows::NSystem::GetNumberOfProcessors()),
   _Long(-1),
   _WindowLog(-1),
-  _ctx(NULL)
+  _ctx(NULL),
+  unpackSize(0)
 {
   _props.clear();
 }
diff --git a/CPP/7zip/Compress/ZstdEncoder.cpp b/CPP/7zip/Compress/ZstdEncoder.cpp
index fcfaaf77..dda80153 100644
--- a/CPP/7zip/Compress/ZstdEncoder.cpp
+++ b/CPP/7zip/Compress/ZstdEncoder.cpp
@@ -263,7 +263,7 @@ STDMETHODIMP CEncoder::Code(ISequentialInStream *inStream,
       if (ZSTD_isError(err)) return E_INVALIDARG;
     }
 
-    if (unpackSize) {
+    if (unpackSize && unpackSize != (UInt64)(Int64)-1) { // size is known
       err = ZSTD_CCtx_setParameter(_ctx, ZSTD_c_srcSizeHint, (int)(unpackSize <= INT_MAX ? unpackSize : INT_MAX));
       if (ZSTD_isError(err)) return E_INVALIDARG;
     }