codec_dav1d: disambiguate "needs more data" and "no more frames" in feed data pump

CHANGELOG.md

diff --git a/CHANGELOG.md b/CHANGELOG.md
index aaad970..d541ad7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@
 - Fixed some warnings (removed unused variables and a bad cast)
 - Add a define in dav1d layer for supporting older dav1d codecs
 - Enabled tons of warnings, and warnings-as-errors; Fixed associated fallout
+- codec_dav1d: disambiguate "needs more data" and "no more frames" in feed data pump
 
 ## [0.3.2] - 2019-07-23
 ### Added

src/codec_dav1d.c

diff --git a/src/codec_dav1d.c b/src/codec_dav1d.c
index a3ac0aa..eb45bef 100644
--- a/src/codec_dav1d.c
+++ b/src/codec_dav1d.c
@@ -86,7 +86,10 @@
     for (;;) {
         avifBool sentData = dav1dFeedData(codec);
         int res = dav1d_get_picture(codec->internal->dav1dContext, &nextFrame);
-        if ((res < 0) && (res != DAV1D_ERR(EAGAIN)) && !sentData) {
+        if ((res == DAV1D_ERR(EAGAIN)) && sentData) {
+            // send more data
+            continue;
+        } else if (res < 0) {
             // No more frames
             return AVIF_FALSE;
         } else {