From 31fe11a57a74c17e92ab40546b9cded139e20eda Mon Sep 17 00:00:00 2001
From: Pascal Massimino <pascal.massimino@gmail.com>
Date: Thu, 15 Sep 2016 02:38:28 -0700
Subject: [PATCH]  fix infinite loop in case of PARTITION0 overflow

max_i4_header_bits_ could drop to zero for difficult image and trigger
a loop. Surprisingly, StatLoop() didn't have this bug.

Change-Id: Idc0f9eadef30a2b2f02041b994f25def30901e36
(cherry picked from commit 21e7537abeb01ad8d5d05c7d27b3f3b22dc85a62)
---
 src/enc/frame.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/enc/frame.c b/src/enc/frame.c
index 138afcf5..57fc471d 100644
--- a/src/enc/frame.c
+++ b/src/enc/frame.c
@@ -816,7 +816,7 @@ int VP8EncTokenLoop(VP8Encoder* const enc) {
            num_pass_left, stats.last_value, stats.value,
            stats.last_q, stats.q, stats.dq);
 #endif
-    if (size_p0 > PARTITION0_SIZE_LIMIT) {
+    if (enc->max_i4_header_bits_ > 0 && size_p0 > PARTITION0_SIZE_LIMIT) {
       ++num_pass_left;
       enc->max_i4_header_bits_ >>= 1;  // strengthen header bit limitation...
       continue;                        // ...and start over