[FFmpeg-devel,2/2] avcodec/vp56rac: delay signaling an error on truncated input

Submitted by Michael Niedermayer on Aug. 20, 2019, 9:51 a.m.

Details

Message ID 20190820095149.32191-2-michael@niedermayer.cc
State Accepted
Commit b6b9ac5698c8f911841b469af77199153278c55c
Headers show

Commit Message

Michael Niedermayer Aug. 20, 2019, 9:51 a.m.
A threshold of 1 is sufficient for simple_dump_cut.webm, 10 is used
just to be sure the next truncated file doesnt cause the same issue

Obvious alternative fixes are to simply accept that the file is broken or to
write some advanced error concealment or to
simply accept that the decoder wont stop at the end of input.

Fixes: Ticket 8069 (artifacts not the differing md5 which was there before 1afd246960202917e244c844c534e9c1e3c323f5)
Fixes: simple_dump_cut.webm
Fixes: regression of 1afd246960202917e244c844c534e9c1e3c323f5

fate-vp5 changes because the last frame is truncated and now handled
differently.

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/vp56.h    | 5 ++++-
 libavcodec/vp56rac.c | 1 +
 tests/ref/fate/vp5   | 2 +-
 3 files changed, 6 insertions(+), 2 deletions(-)

Comments

Michael Niedermayer Sept. 11, 2019, 8:39 p.m.
On Tue, Aug 20, 2019 at 11:51:49AM +0200, Michael Niedermayer wrote:
> A threshold of 1 is sufficient for simple_dump_cut.webm, 10 is used
> just to be sure the next truncated file doesnt cause the same issue
> 
> Obvious alternative fixes are to simply accept that the file is broken or to
> write some advanced error concealment or to
> simply accept that the decoder wont stop at the end of input.
> 
> Fixes: Ticket 8069 (artifacts not the differing md5 which was there before 1afd246960202917e244c844c534e9c1e3c323f5)
> Fixes: simple_dump_cut.webm
> Fixes: regression of 1afd246960202917e244c844c534e9c1e3c323f5
> 
> fate-vp5 changes because the last frame is truncated and now handled
> differently.
> 
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
>  libavcodec/vp56.h    | 5 ++++-
>  libavcodec/vp56rac.c | 1 +
>  tests/ref/fate/vp5   | 2 +-
>  3 files changed, 6 insertions(+), 2 deletions(-)

will apply

[...]

Patch hide | download patch | download mbox

diff --git a/libavcodec/vp56.h b/libavcodec/vp56.h
index 84b2f6c94b..65cf46870a 100644
--- a/libavcodec/vp56.h
+++ b/libavcodec/vp56.h
@@ -89,6 +89,7 @@  typedef struct VP56RangeCoder {
     const uint8_t *buffer;
     const uint8_t *end;
     unsigned int code_word;
+    int end_reached;
 } VP56RangeCoder;
 
 typedef struct VP56RefDc {
@@ -235,7 +236,9 @@  int ff_vp56_init_range_decoder(VP56RangeCoder *c, const uint8_t *buf, int buf_si
  */
 static av_always_inline int vpX_rac_is_end(VP56RangeCoder *c)
 {
-    return c->end <= c->buffer && c->bits >= 0;
+    if (c->end <= c->buffer && c->bits >= 0)
+        c->end_reached ++;
+    return c->end_reached > 10;
 }
 
 static av_always_inline unsigned int vp56_rac_renorm(VP56RangeCoder *c)
diff --git a/libavcodec/vp56rac.c b/libavcodec/vp56rac.c
index e70302bf85..64fb6a99b4 100644
--- a/libavcodec/vp56rac.c
+++ b/libavcodec/vp56rac.c
@@ -43,6 +43,7 @@  int ff_vp56_init_range_decoder(VP56RangeCoder *c, const uint8_t *buf, int buf_si
     c->bits = -16;
     c->buffer = buf;
     c->end = buf + buf_size;
+    c->end_reached = 0;
     if (buf_size < 1)
         return AVERROR_INVALIDDATA;
     c->code_word = bytestream_get_be24(&c->buffer);
diff --git a/tests/ref/fate/vp5 b/tests/ref/fate/vp5
index 2469a3ec21..09ebe62b25 100644
--- a/tests/ref/fate/vp5
+++ b/tests/ref/fate/vp5
@@ -249,4 +249,4 @@ 
 0,        243,        243,        1,   233472, 0x6f530ac6
 0,        244,        244,        1,   233472, 0x94f7466c
 0,        245,        245,        1,   233472, 0xa8c1d365
-0,        246,        246,        1,   233472, 0xbf73f1b7
+0,        246,        246,        1,   233472, 0x4f3ef38c