diff --unified --recursive --text --new-file --color ffmpeg-7.1.3.old/libavformat/mov.c ffmpeg-7.1.3/libavformat/mov.c
--- ffmpeg-7.1.3.old/libavformat/mov.c	2025-11-21 09:15:18.000000000 +0800
+++ ffmpeg-7.1.3/libavformat/mov.c	2026-05-13 15:25:48.766746834 +0800
@@ -7905,7 +7905,7 @@
     }
 
     for (i = 0; i < sample->subsample_count; i++) {
-        if (sample->subsamples[i].bytes_of_clear_data + sample->subsamples[i].bytes_of_protected_data > size) {
+        if (sample->subsamples[i].bytes_of_clear_data + (int64_t)sample->subsamples[i].bytes_of_protected_data > size) {
             av_log(c->fc, AV_LOG_ERROR, "subsample size exceeds the packet size left\n");
             return AVERROR_INVALIDDATA;
         }
@@ -7960,7 +7960,7 @@
     }
 
     for (i = 0; i < sample->subsample_count; i++) {
-        if (sample->subsamples[i].bytes_of_clear_data + sample->subsamples[i].bytes_of_protected_data > size) {
+        if (sample->subsamples[i].bytes_of_clear_data + (int64_t)sample->subsamples[i].bytes_of_protected_data > size) {
             av_log(c->fc, AV_LOG_ERROR, "subsample size exceeds the packet size left\n");
             return AVERROR_INVALIDDATA;
         }
@@ -8022,7 +8022,7 @@
     }
 
     for (i = 0; i < sample->subsample_count; i++) {
-        if (sample->subsamples[i].bytes_of_clear_data + sample->subsamples[i].bytes_of_protected_data > size) {
+        if (sample->subsamples[i].bytes_of_clear_data + (int64_t)sample->subsamples[i].bytes_of_protected_data > size) {
             av_log(c->fc, AV_LOG_ERROR, "subsample size exceeds the packet size left\n");
             return AVERROR_INVALIDDATA;
         }
@@ -8087,7 +8087,7 @@
     }
 
     for (i = 0; i < sample->subsample_count; i++) {
-        if (sample->subsamples[i].bytes_of_clear_data + sample->subsamples[i].bytes_of_protected_data > size) {
+        if (sample->subsamples[i].bytes_of_clear_data + (int64_t)sample->subsamples[i].bytes_of_protected_data > size) {
             av_log(c->fc, AV_LOG_ERROR, "subsample size exceeds the packet size left\n");
             return AVERROR_INVALIDDATA;
         }