[FFmpeg-devel] [PATCH] avcodec/proresenc_kostya: Remove harmful check

Andreas Rheinhardt andreas.rheinhardt at outlook.com
Thu Apr 8 00:15:09 EEST 2021

The ProRes encoder allocates huge worst-case buffers just to be safe;
and for huge resolutions (8k in this case) these can be so big that the
number of bits does no longer fit into a (signed 32-bit) int; this means
that one must no longer use the parts of the PutBits API that deal with
bit counters. Yet proresenc_kostya did it, namely for a check about
whether we are already beyond the end. Yet this check is unnecessary
nowadays, because the PutBits API comes with automatic checks (with
a log message and a av_assert2() in put_bits() and an av_assert0() in
flush_put_bits()), so this is unnecessary. So simply remove the check.

Fixes ticket #9173.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
I actually pondered removing said check when I wrote
f9d1528fc900dac4975ce785dd95004daeacec39 (which stopped using
intermediate bitcounts).

 libavcodec/proresenc_kostya.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/libavcodec/proresenc_kostya.c b/libavcodec/proresenc_kostya.c
index d8edd12f34..54fc6707a1 100644
--- a/libavcodec/proresenc_kostya.c
+++ b/libavcodec/proresenc_kostya.c
@@ -619,11 +619,6 @@ static int encode_slice(AVCodecContext *avctx, const AVFrame *pic,
         sizes[i]   = put_bytes_output(pb) - total_size;
         total_size = put_bytes_output(pb);
-        if (put_bits_left(pb) < 0) {
-            av_log(avctx, AV_LOG_ERROR,
-                   "Underestimated required buffer size.\n");
-            return AVERROR_BUG;
-        }
     return total_size;

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