shithub: libvpx

Info  •  Files  •  Log  •  Branches

Prevent encoder crash caused by row tile dependencies

In multi-thread case, the encoder may crash if using encoder option
tile-rows > 0. To prevent that, force tile-rows=0 in this situation.
This is a workaround for WebM issue 1095:
https://bugs.chromium.org/p/webm/issues/detail?id=1095

The further fix can be done by adding synchronizations after a tile
row is encoded. But this will hurt multi-threaded encoder performance.
So, it is recommended to use tile-rows=0 while encoding with threads
> 1.

Change-Id: I656cbcc200f8d0410d09530e7981ad8f32fe7bc9

--- a/vp9/vp9_cx_iface.c

+++ b/vp9/vp9_cx_iface.c

@@ -486,7 +486,13 @@

   oxcf->content = extra_cfg->content;

   oxcf->tile_columns = extra_cfg->tile_columns;

-  oxcf->tile_rows    = extra_cfg->tile_rows;

+

+  // The dependencies between row tiles cause error in multi-threaded encoding.

+  // For now, it is forced to be 0 in this case.

+  if (oxcf->max_threads > 1 && oxcf->tile_columns > 0)

+    oxcf->tile_rows  = 0;

+  else

+    oxcf->tile_rows  = extra_cfg->tile_rows;

   oxcf->error_resilient_mode         = cfg->g_error_resilient;

   oxcf->frame_parallel_decoding_mode = extra_cfg->frame_parallel_decoding_mode;

--- a/vpxenc.c

+++ b/vpxenc.c

@@ -380,7 +380,8 @@

 static const arg_def_t tile_cols = ARG_DEF(

     NULL, "tile-columns", 1, "Number of tile columns to use, log2");

 static const arg_def_t tile_rows = ARG_DEF(

-    NULL, "tile-rows", 1, "Number of tile rows to use, log2");

+    NULL, "tile-rows", 1,

+    "Number of tile rows to use, log2 (set to 0 while threads > 1)");

 static const arg_def_t lossless = ARG_DEF(

     NULL, "lossless", 1, "Lossless mode (0: false (default), 1: true)");

 static const arg_def_t frame_parallel_decoding = ARG_DEF(