[FFmpeg-devel] [PATCH] mjpegenc: make optimal huffman coding the default

[Michael Niedermayer]

On Wed, Feb 22, 2017 at 10:47:13PM +0000, Rostislav Pehlivanov wrote:
> Its been extensively tested and it gives gain for practically free, so
> make it enabled by default.
> 
> Signed-off-by: Rostislav Pehlivanov <atomnuker at gmail.com>
> ---
>  libavcodec/mjpegenc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/libavcodec/mjpegenc.c b/libavcodec/mjpegenc.c
> index cc917edb7f..03c3d0ab13 100644
> --- a/libavcodec/mjpegenc.c
> +++ b/libavcodec/mjpegenc.c
> @@ -444,7 +444,7 @@ FF_MPV_COMMON_OPTS
>      { "left",   NULL, 0, AV_OPT_TYPE_CONST, { .i64 = 1 }, INT_MIN, INT_MAX, VE, "pred" },
>      { "plane",  NULL, 0, AV_OPT_TYPE_CONST, { .i64 = 2 }, INT_MIN, INT_MAX, VE, "pred" },
>      { "median", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = 3 }, INT_MIN, INT_MAX, VE, "pred" },
> -{ "huffman", "Huffman table strategy", OFFSET(huffman), AV_OPT_TYPE_INT, { .i64 = HUFFMAN_TABLE_DEFAULT }, 0, NB_HUFFMAN_TABLE_OPTION - 1, VE, "huffman" },
> +{ "huffman", "Huffman table strategy", OFFSET(huffman), AV_OPT_TYPE_INT, { .i64 = HUFFMAN_TABLE_OPTIMAL }, 0, NB_HUFFMAN_TABLE_OPTION - 1, VE, "huffman" },
>      { "default", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = HUFFMAN_TABLE_DEFAULT }, INT_MIN, INT_MAX, VE, "huffman" },
>      { "optimal", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = HUFFMAN_TABLE_OPTIMAL }, INT_MIN, INT_MAX, VE, "huffman" },
>  { NULL},
> -- 
> 2.12.0.rc1.440.g5b76565f74


./ffmpeg -i lena.pnm   -threads 2 -thread_type slice file.jpg

fails with

Assertion n <= 31 && value < (1U << n) failed at libavcodec/put_bits.h:157

I dont think slice threads work with optimal huffman 

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

During times of universal deceit, telling the truth becomes a
revolutionary act. -- George Orwell
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