Allow reading of growing avi files (ie currently being written)

This uses the RIFF header stored size to figure out the expected AVI file size, instead
of the actual file. To work fully it requires handling failed avio_seek() instead
of assuming they always succeed.

Some fate file has been cut off and contains half a frame at the end which previously
was not output during demuxing. This frame is now output to encoder, thus fate
diff update.

libavformat/avidec.c

@@ -157,7 +157,7 @@ static int read_braindead_odml_indx(AVFormatContext *s, int frame_num){
     AVIStream *ast;
     int i;
     int64_t last_pos= -1;
-    int64_t filesize= avio_size(s->pb);
+    int64_t filesize= avi->fsize;
 
     av_dlog(s, "longs_pre_entry:%d index_type:%d entries_in_use:%d chunk_id:%X base:%16"PRIX64"\n",
             longs_pre_entry,index_type, entries_in_use, chunk_id, base);
@@ -372,7 +372,7 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
     av_log(avi, AV_LOG_DEBUG, "use odml:%d\n", avi->use_odml);
 
     avi->fsize = avio_size(pb);
-    if(avi->fsize<=0)
+    if(avi->fsize<=0 || avi->fsize < avi->riff_end)
         avi->fsize= avi->riff_end == 8 ? INT64_MAX : avi->riff_end;
 
     /* first list tag */
@@ -398,7 +398,7 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
             if (tag1 == MKTAG('m', 'o', 'v', 'i')) {
                 avi->movi_list = avio_tell(pb) - 4;
                 if(size) avi->movi_end = avi->movi_list + size + (size & 1);
-                else     avi->movi_end = avio_size(pb);
+                else     avi->movi_end = avi->fsize;
                 av_dlog(NULL, "movi end=%"PRIx64"\n", avi->movi_end);
                 goto end_of_header;
             }
@@ -731,7 +731,7 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
                                         "I will ignore it and try to continue anyway.\n");
                 if (s->error_recognition >= FF_ER_EXPLODE) goto fail;
                 avi->movi_list = avio_tell(pb) - 4;
-                avi->movi_end  = avio_size(pb);
+                avi->movi_end  = avi->fsize;
                 goto end_of_header;
             }
             /* skip tag */

tests/ref/fate/aasc

@@ -21,3 +21,4 @@
 0, 72000, 168000, 0x646fa087
 0, 75600, 168000, 0x404450a2
 0, 79200, 168000, 0x5214c456
+0, 82800, 168000, 0xe573025c

tests/ref/fate/cvid

@@ -76,3 +76,4 @@
 0, 562500, 112400, 0xe4394f1f
 0, 570000, 112400, 0x8ca8649f
 0, 577500, 112400, 0x804d44eb
+0, 585000, 112400, 0x3864488b

tests/ref/fate/fraps-v5

@@ -56,3 +56,4 @@
 0, 165000, 145152, 0x80448031
 0, 168000, 145152, 0xe3b1fbf7
 0, 171000, 145152, 0xa00395a4
+0, 174000, 145152, 0xdf3b4fce

tests/ref/fate/truemotion1-24

@@ -30,6 +30,7 @@
 1, 82898, 10832, 0x3c746fbe
 0, 84000, 69120, 0x5876d758
 1, 88424, 10832, 0x05f3b08a
+0, 90000, 69120, 0x45e7dd5c
 1, 93951, 10832, 0xa6560483
 1, 99478, 10832, 0xd98a8e19
 1, 105004, 10832, 0xf98a0b2e

tests/ref/fate/vp5

@@ -244,3 +244,4 @@
 0, 912161, 233472, 0x6f530ac6
 0, 915915, 233472, 0x94f7466c
 0, 919669, 233472, 0xa8c1d365
+0, 923423, 233472, 0xedcff050

tests/ref/fate/zmbv-8bit

@@ -273,3 +273,4 @@
 0, 349284, 192000, 0xd08e49d1
 0, 350568, 192000, 0xd08e49d1
 0, 351852, 192000, 0xd08e49d1
+0, 353136, 192000, 0x1f34135f