avformat/mux: Remove redundant checks for write errors

If writing a packet didn't directly return an error, the AVIOContext's
error flag is checked for errors (if existing) by write_packet(). And if
write_packet() didn't indicate an error, its callers checked the error
flag of the AVIOContext (if existing). The latter check is redundant.

The reason for checking twice lies in the FFmpeg-Libav split: The check
in write_packet() has been added in 9ad1e0c1 in Libav. FFmpeg already
had the other checks (since aec9390a), but when 9ad1e0c1 was merged
(in 1f1c1008), no one noticed the redundant checks.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavformat/mux.c

@@ -913,8 +913,6 @@ int av_write_frame(AVFormatContext *s, AVPacket *pkt)
 #endif
 
     ret = write_packet(s, pkt);
-    if (ret >= 0 && s->pb && s->pb->error < 0)
-        ret = s->pb->error;
 
     if (ret >= 0)
         s->streams[pkt->stream_index]->nb_frames++;
@@ -1246,8 +1244,6 @@ int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt)
 
         if (ret < 0)
             return ret;
-        if(s->pb && s->pb->error)
-            return s->pb->error;
     }
 fail:
     av_packet_unref(pkt);
@@ -1274,8 +1270,6 @@ int av_write_trailer(AVFormatContext *s)
 
         if (ret < 0)
             goto fail;
-        if(s->pb && s->pb->error)
-            goto fail;
     }
 
 fail: