diff --git a/libavformat/mov.c b/libavformat/mov.c
index 278dec6765..444aca5235 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -6650,38 +6650,6 @@ finish:
     return ret;
 }
 
-/**
- * Tries to read the given number of bytes from the stream and puts it in a
- * newly allocated buffer.  This reads in small chunks to avoid allocating large
- * memory if the file contains an invalid/malicious size value.
- */
-static int mov_try_read_block(AVIOContext *pb, size_t size, uint8_t **data)
-{
-    const unsigned int block_size = 1024 * 1024;
-    uint8_t *buffer = NULL;
-    unsigned int alloc_size = 0, offset = 0;
-    while (offset < size) {
-        unsigned int new_size =
-            alloc_size >= INT_MAX - block_size ? INT_MAX : alloc_size + block_size;
-        uint8_t *new_buffer = av_fast_realloc(buffer, &alloc_size, new_size);
-        unsigned int to_read = FFMIN(size, alloc_size) - offset;
-        if (!new_buffer) {
-            av_free(buffer);
-            return AVERROR(ENOMEM);
-        }
-        buffer = new_buffer;
-
-        if (avio_read(pb, buffer + offset, to_read) != to_read) {
-            av_free(buffer);
-            return AVERROR_INVALIDDATA;
-        }
-        offset += to_read;
-    }
-
-    *data = buffer;
-    return 0;
-}
-
 static int mov_read_saiz(MOVContext *c, AVIOContext *pb, MOVAtom atom)
 {
     MOVEncryptionIndex *encryption_index;
@@ -6737,15 +6705,24 @@ static int mov_read_saiz(MOVContext *c, AVIOContext *pb, MOVAtom atom)
 
     encryption_index->auxiliary_info_default_size = avio_r8(pb);
     sample_count = avio_rb32(pb);
-    encryption_index->auxiliary_info_sample_count = sample_count;
 
     if (encryption_index->auxiliary_info_default_size == 0) {
-        ret = mov_try_read_block(pb, sample_count, &encryption_index->auxiliary_info_sizes);
-        if (ret < 0) {
-            av_log(c->fc, AV_LOG_ERROR, "Failed to read the auxiliary info\n");
+        encryption_index->auxiliary_info_sizes = av_malloc(sample_count);
+        if (!encryption_index->auxiliary_info_sizes)
+            return AVERROR(ENOMEM);
+
+        ret = avio_read(pb, encryption_index->auxiliary_info_sizes, sample_count);
+        if (ret != sample_count) {
+            av_freep(&encryption_index->auxiliary_info_sizes);
+
+            if (ret >= 0)
+                ret = AVERROR_INVALIDDATA;
+            av_log(c->fc, AV_LOG_ERROR, "Failed to read the auxiliary info, %s\n",
+                   av_err2str(ret));
             return ret;
         }
     }
+    encryption_index->auxiliary_info_sample_count = sample_count;
 
     if (encryption_index->auxiliary_offsets_count) {
         return mov_parse_auxiliary_info(c, sc, pb, encryption_index);
@@ -6914,9 +6891,19 @@ static int mov_read_pssh(MOVContext *c, AVIOContext *pb, MOVAtom atom)
     }
 
     extra_data_size = avio_rb32(pb);
-    ret = mov_try_read_block(pb, extra_data_size, &extra_data);
-    if (ret < 0)
+    extra_data = av_malloc(extra_data_size);
+    if (!extra_data) {
+        ret = AVERROR(ENOMEM);
         goto finish;
+    }
+    ret = avio_read(pb, extra_data, extra_data_size);
+    if (ret != extra_data_size) {
+        av_free(extra_data);
+
+        if (ret >= 0)
+            ret = AVERROR_INVALIDDATA;
+        goto finish;
+    }
 
     av_freep(&info->data);  // malloc(0) may still allocate something.
     info->data = extra_data;