Michael Niedermayer:
> On Wed, Mar 26, 2025 at 04:08:55AM +0000, Andreas Rheinhardt wrote:
>> ffmpeg | branch: master | Andreas Rheinhardt
>> <andreas.rheinha...@outlook.com> | Mon Mar 3 02:36:55 2025 +0100|
>> [24dbc4c2e82481f89d6fcacee1949e5038c5c2fc] | committer: Andreas Rheinhardt
>>
>> avcodec/mjpegenc: Simplify allocating huffman table
>>
>> Reuse the already computed value of macroblocks; use an array
>> instead of a switch, evaluate 64 * sizeof(MJpegHuffmanCode)
>> at compile-time.
>>
>> Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@outlook.com>
>>
>>> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=24dbc4c2e82481f89d6fcacee1949e5038c5c2fc
>> ---
>>
>> libavcodec/mjpegenc.c | 24 ++++++++++--------------
>> 1 file changed, 10 insertions(+), 14 deletions(-)
>
> Breaks: (did not investigate why)
>
> ./ffmpeg -i lena.pnm -strict -1 -s 4096x2048 -bitexact -y
> /tmp/file-4096x2048.m2v && ./ffmpeg -i /tmp/file-4096x2048.m2v -y -bitexact
> /tmp/file-4096x2048-dec.jpg
>
> [vost#0:0/mjpeg @ 0x5576d6b7ab00] [enc:mjpeg @ 0x5576d6b79580] Error while
> opening encoder - maybe incorrect parameters such as bit_rate, rate, width or
> height.
> [vf#0:0 @ 0x5576d6b7f140] Error sending frames to consumers: Cannot allocate
> memory
> [vf#0:0 @ 0x5576d6b7f140] Task finished with error code: -12 (Cannot allocate
> memory)
> [vf#0:0 @ 0x5576d6b7f140] Terminating thread with return code -12 (Cannot
> allocate memory)
> [vost#0:0/mjpeg @ 0x5576d6b7ab00] [enc:mjpeg @ 0x5576d6b79580] Could not open
> encoder before EOF
> [vost#0:0/mjpeg @ 0x5576d6b7ab00] Task finished with error code: -22 (Invalid
> argument)
> [vost#0:0/mjpeg @ 0x5576d6b7ab00] Terminating thread with return code -22
> (Invalid argument)
> [out#0/image2 @ 0x5576d6b7ec80] Nothing was written into output file, because
> at least one of its streams received no packets.
>
Patch attached. Thanks for testing.
- Andreas
From 11d68061103257173a3c065b176cc84ad63885a7 Mon Sep 17 00:00:00 2001
From: Andreas Rheinhardt <andreas.rheinha...@outlook.com>
Date: Thu, 27 Mar 2025 03:03:02 +0100
Subject: [PATCH] avcodec/mjpegenc: Don't allocate unnecessarily much memory
We need to allocate space for 64 coefficients per block;
24dbc4c2e82481f89d6fcacee1949e5038c5c2fc wanted to
perform the calculation 64*sizeof(MJpegHuffmanCode)
at compile time, yet in the end did it in a way that
made it allocate 64 times as much memory as needed.
Reported-by: Michael Niedermayer <mich...@niedermayer.cc>
Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@outlook.com>
---
libavcodec/mjpegenc.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/libavcodec/mjpegenc.c b/libavcodec/mjpegenc.c
index 668065011c..214e2b0ec1 100644
--- a/libavcodec/mjpegenc.c
+++ b/libavcodec/mjpegenc.c
@@ -291,13 +291,12 @@ static int alloc_huffman(MJPEGEncContext *const m2)
static const char blocks_per_mb[] = {
[CHROMA_420] = 6, [CHROMA_422] = 8, [CHROMA_444] = 12
};
- size_t num_blocks, num_codes;
+ size_t num_blocks;
// Make sure we have enough space to hold this frame.
num_blocks = s->c.mb_num * blocks_per_mb[s->c.chroma_format];
- num_codes = num_blocks * 64;
- m->huff_buffer = av_malloc_array(num_codes,
+ m->huff_buffer = av_malloc_array(num_blocks,
64 /* codes per MB */ * sizeof(MJpegHuffmanCode));
if (!m->huff_buffer)
return AVERROR(ENOMEM);
--
2.45.2
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