Allow reading of growing avi files (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 the fate diff update.

Bug-Id: 261
Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>

libavformat/avidec.c

@@ -151,7 +151,7 @@ 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 "
@@ -374,7 +374,7 @@ static int avi_read_header(AVFormatContext *s)
         return ret;
 
     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 */
@@ -402,7 +402,7 @@ static int avi_read_header(AVFormatContext *s)
                 if (size)
                     avi->movi_end = avi->movi_list + size + (size & 1);
                 else
-                    avi->movi_end = avio_size(pb);
+                    avi->movi_end = avi->fsize;
                 av_dlog(NULL, "movi end=%"PRIx64"\n", avi->movi_end);
                 goto end_of_header;
             } else if (tag1 == MKTAG('I', 'N', 'F', 'O'))
@@ -774,7 +774,7 @@ static int avi_read_header(AVFormatContext *s)
                 if (s->error_recognition & AV_EF_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

@@ -22,3 +22,4 @@
 0,         20,         20,        1,   168000, 0x7a2b1006
 0,         21,         21,        1,   168000, 0xc7ca1345
 0,         22,         22,        1,   168000, 0x8841c413
+0,         23,         23,        1,   168000, 0xbaed0290

tests/ref/fate/cllc-argb

@@ -3,3 +3,4 @@
 0,          1,          1,        1,  3686400, 0x66a45032
 0,          2,          2,        1,  3686400, 0xdf0c861f
 0,          3,          3,        1,  3686400, 0xa4a68cdb
+0,          4,          4,        1,  3686400, 0xb5f9526e

tests/ref/fate/cllc-rgb

@@ -13,3 +13,4 @@
 0,         11,         11,        1,   921600, 0x4d7488fa
 0,         12,         12,        1,   921600, 0x16b9c9c9
 0,         13,         13,        1,   921600, 0xa0a4f77f
+0,         14,         14,        1,   921600, 0xf61a5501

tests/ref/fate/cllc-yuy2-noblock

@@ -14,3 +14,4 @@
 0,         12,         12,        1,   614400, 0x2d8fd7cc
 0,         13,         13,        1,   614400, 0xd9dfc2ef
 0,         14,         14,        1,   614400, 0xaf95cef0
+0,         15,         15,        1,   614400, 0x6dcf5ed6

tests/ref/fate/cvid-partial

@@ -77,3 +77,4 @@
 0,         75,         75,        1,   112400, 0xe4394f1f
 0,         76,         76,        1,   112400, 0x8ca8649f
 0,         77,         77,        1,   112400, 0x804d44eb
+0,         78,         78,        1,   112400, 0x3864488b

tests/ref/fate/fic-avi

@@ -119,3 +119,4 @@
 0,        117,        117,        1,  1566720, 0xfe83b964
 0,        118,        118,        1,  1566720, 0x25dc30a6
 0,        119,        119,        1,  1566720, 0x25dc30a6
+0,        120,        120,        1,  1566720, 0x25dc30a6

tests/ref/fate/truemotion1-24

@@ -14,3 +14,4 @@
 0,         12,         12,        1,    69120, 0xf55d74c7
 0,         13,         13,        1,    69120, 0xb5082ca7
 0,         14,         14,        1,    69120, 0x5876d758
+0,         15,         15,        1,    69120, 0x45e7dd5c

tests/ref/fate/vp5

@@ -245,3 +245,4 @@
 0,        243,        243,        1,   233472, 0x6f530ac6
 0,        244,        244,        1,   233472, 0x94f7466c
 0,        245,        245,        1,   233472, 0xa8c1d365
+0,        246,        246,        1,   233472, 0xedcff050

tests/ref/fate/zmbv-8bit

@@ -274,3 +274,4 @@
 0,        272,        272,        1,   192000, 0xd08e49d1
 0,        273,        273,        1,   192000, 0xd08e49d1
 0,        274,        274,        1,   192000, 0xd08e49d1
+0,        275,        275,        1,   192000, 0x1f34135f