[FFmpeg-devel] [PATCH] Flush decoders correctly in avformat_find_stream_info().

[Reimar Döffinger]

The decoders should not only be flushed on EOF or error, but also when
e.g. probe size was reached.
It is best to just always flush by default and only disable it
explicitly when we know that we have everything we need.
Fixes trac ticket #879.

Signed-off-by: Reimar Döffinger <Reimar.Doeffinger at gmx.de>
---
 libavformat/utils.c |   51 ++++++++++++++++++++++++++++-----------------------
 1 files changed, 28 insertions(+), 23 deletions(-)

diff --git a/libavformat/utils.c b/libavformat/utils.c
index 8ed4674..d5604c4 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -2390,6 +2390,7 @@ int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
     AVPacket pkt1, *pkt;
     int64_t old_offset = avio_tell(ic->pb);
     int orig_nb_streams = ic->nb_streams;        // new streams might appear, no options for those
+    int flush_codecs = 1;
 
     for(i=0;i<ic->nb_streams;i++) {
         AVCodec *codec;
@@ -2469,6 +2470,7 @@ int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
                 /* if we found the info for all the codecs, we can stop */
                 ret = count;
                 av_log(ic, AV_LOG_DEBUG, "All info found\n");
+                flush_codecs = 0;
                 break;
             }
         }
@@ -2487,29 +2489,6 @@ int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
 
         if (ret < 0) {
             /* EOF or error*/
-            AVPacket empty_pkt = { 0 };
-            int err;
-            av_init_packet(&empty_pkt);
-
-            ret = -1; /* we could not have all the codec parameters before EOF */
-            for(i=0;i<ic->nb_streams;i++) {
-                st = ic->streams[i];
-
-                /* flush the decoders */
-                while ((err = try_decode_frame(st, &empty_pkt,
-                                               (options && i < orig_nb_streams) ?
-                                                &options[i] : NULL)) >= 0)
-                    if (has_codec_parameters(st->codec))
-                        break;
-
-                if (!has_codec_parameters(st->codec)){
-                    char buf[256];
-                    avcodec_string(buf, sizeof(buf), st->codec, 0);
-                    av_log(ic, AV_LOG_WARNING, "Could not find codec parameters (%s)\n", buf);
-                } else {
-                    ret = 0;
-                }
-            }
             break;
         }
 
@@ -2585,6 +2564,32 @@ int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
         count++;
     }
 
+    if (flush_codecs) {
+        AVPacket empty_pkt = { 0 };
+        int err;
+        av_init_packet(&empty_pkt);
+
+        ret = -1; /* we could not have all the codec parameters before EOF */
+        for(i=0;i<ic->nb_streams;i++) {
+            st = ic->streams[i];
+
+            /* flush the decoders */
+            while ((err = try_decode_frame(st, &empty_pkt,
+                                           (options && i < orig_nb_streams) ?
+                                            &options[i] : NULL)) >= 0)
+                if (has_codec_parameters(st->codec))
+                    break;
+
+            if (!has_codec_parameters(st->codec)){
+                char buf[256];
+                avcodec_string(buf, sizeof(buf), st->codec, 0);
+                av_log(ic, AV_LOG_WARNING, "Could not find codec parameters (%s)\n", buf);
+            } else {
+                ret = 0;
+            }
+        }
+    }
+
     // close codecs which were opened in try_decode_frame()
     for(i=0;i<ic->nb_streams;i++) {
         st = ic->streams[i];
-- 
1.7.8.2