From: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
To: ffmpeg-devel@ffmpeg.org
Subject: Re: [FFmpeg-devel] [PATCH 1/6] avcodec/mpegvideodata: Make DC scale tables smaller
Date: Sun, 30 Oct 2022 12:13:55 +0100
Message-ID: <AS8P250MB0744609E8BB1BD233389ECA38F349@AS8P250MB0744.EURP250.PROD.OUTLOOK.COM> (raw)
In-Reply-To: <AS8P250MB074477D545EEBC518DE29CB48F329@AS8P250MB0744.EURP250.PROD.OUTLOOK.COM>
Andreas Rheinhardt:
> These tables are only accessed in ff_set_qscale()
> which only accesses values 1..31 as well as in
> encode_picture() in mpegvideo_enc.c, accessing
> the value with index 8. So make these tables smaller.
>
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
> ---
> libavcodec/mpegvideodata.c | 32 ++++----------------------------
> libavcodec/mpegvideodata.h | 2 +-
> 2 files changed, 5 insertions(+), 29 deletions(-)
>
> diff --git a/libavcodec/mpegvideodata.c b/libavcodec/mpegvideodata.c
> index da0638e052..b98e90cf43 100644
> --- a/libavcodec/mpegvideodata.c
> +++ b/libavcodec/mpegvideodata.c
> @@ -30,46 +30,22 @@ const uint8_t ff_mpeg2_non_linear_qscale[32] = {
> 56, 64, 72, 80, 88, 96, 104, 112,
> };
>
> -const uint8_t ff_mpeg1_dc_scale_table[128] = {
> - 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
> - 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
> - 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
> - 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
> - 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
> - 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
> +const uint8_t ff_mpeg1_dc_scale_table[32] = {
> 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
> 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
> };
>
> -static const uint8_t mpeg2_dc_scale_table1[128] = {
> - 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
> - 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
> - 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
> - 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
> - 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
> - 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
> +static const uint8_t mpeg2_dc_scale_table1[32] = {
> 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
> 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
> };
>
> -static const uint8_t mpeg2_dc_scale_table2[128] = {
> - 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
> - 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
> - 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
> - 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
> - 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
> - 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
> +static const uint8_t mpeg2_dc_scale_table2[32] = {
> 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
> 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
> };
>
> -static const uint8_t mpeg2_dc_scale_table3[128] = {
> - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
> - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
> - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
> - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
> - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
> - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
> +static const uint8_t mpeg2_dc_scale_table3[32] = {
> 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
> 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
> };
> diff --git a/libavcodec/mpegvideodata.h b/libavcodec/mpegvideodata.h
> index 14f4806d66..cf783ef31c 100644
> --- a/libavcodec/mpegvideodata.h
> +++ b/libavcodec/mpegvideodata.h
> @@ -25,7 +25,7 @@
> extern const uint8_t ff_alternate_horizontal_scan[64];
> extern const uint8_t ff_alternate_vertical_scan[64];
>
> -extern const uint8_t ff_mpeg1_dc_scale_table[128];
> +extern const uint8_t ff_mpeg1_dc_scale_table[32];
> extern const uint8_t * const ff_mpeg2_dc_scale_table[4];
>
> extern const uint8_t ff_mpeg2_non_linear_qscale[32];
Will apply this patchset tomorrow unless there are objections.
- Andreas
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prev parent reply other threads:[~2022-10-30 11:13 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-28 14:48 Andreas Rheinhardt
2022-10-28 14:49 ` [FFmpeg-devel] [PATCH 2/6] avcodec/mpegvideodata: Join mpeg1/2 dc scale tables Andreas Rheinhardt
2022-10-28 14:49 ` [FFmpeg-devel] [PATCH 3/6] avcodec/mpegvideodata: Mark tables as hidden Andreas Rheinhardt
2022-10-28 14:49 ` [FFmpeg-devel] [PATCH 4/6] avcodec/flvdec, intelh263dec: Remove redundant assignments Andreas Rheinhardt
2022-10-28 14:49 ` [FFmpeg-devel] [PATCH 5/6] avcodec/rv34: Remove always-true/false checks Andreas Rheinhardt
2022-10-28 14:49 ` [FFmpeg-devel] [PATCH 6/6] avcodec/vc1data: Mark tables as hidden Andreas Rheinhardt
2022-10-30 11:13 ` Andreas Rheinhardt [this message]
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