From mboxrd@z Thu Jan 1 00:00:00 1970
Return-Path: <ffmpeg-devel-bounces@ffmpeg.org>
Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100])
by master.gitmailbox.com (Postfix) with ESMTPS id 80F054D8F2
for <ffmpegdev@gitmailbox.com>; Mon, 21 Apr 2025 02:34:23 +0000 (UTC)
Received: from [127.0.1.1] (localhost [127.0.0.1])
by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 328CC68A114;
Mon, 21 Apr 2025 05:34:00 +0300 (EEST)
Received: from mail-pf1-f180.google.com (mail-pf1-f180.google.com
[209.85.210.180])
by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 79DFD687EB0
for <ffmpeg-devel@ffmpeg.org>; Mon, 21 Apr 2025 05:33:52 +0300 (EEST)
Received: by mail-pf1-f180.google.com with SMTP id
d2e1a72fcca58-736b98acaadso3237450b3a.1
for <ffmpeg-devel@ffmpeg.org>; Sun, 20 Apr 2025 19:33:52 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
d=emma-gg.20230601.gappssmtp.com; s=20230601; t=1745202830; x=1745807630;
darn=ffmpeg.org;
h=content-transfer-encoding:mime-version:references:in-reply-to
:message-id:date:subject:cc:to:from:from:to:cc:subject:date
:message-id:reply-to;
bh=WHhYKXFvmnYZ6aegIYf09tu5zxEa03KfAkSTpNFDZlI=;
b=2h6oRhFe+FrGJxrrpF5Mbm4qmvomLPddGfFwWaH2wKfpoQIPbzcfzbcqJcy1juvxKe
a9bX4numr6qdYWxfw5myxg9rpCMKpZIFov0oAh7shb0uGxqTGlZ6CYPo+lvVm+p+1Cpp
XHOeO7sp+GSVuKBzeuJzMBC2YJCj4D7JpjeC31pD+dBlFsQ7j4/x0GpAGUg3h6DZSvo+
SG1z73PpV48zC1LPotkMkCzyBkqC4+hHnAG6fEs4NqSUW+zY5PYNF3hhDLIWgPs/zbTb
VL4z5JmgKle2AeOiB0tXZ0KcbTUsc0aUSlxi/UL7YPaROZ7xRr35spWok/zWvCceXNkX
nceg==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
d=1e100.net; s=20230601; t=1745202830; x=1745807630;
h=content-transfer-encoding:mime-version:references:in-reply-to
:message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc
:subject:date:message-id:reply-to;
bh=WHhYKXFvmnYZ6aegIYf09tu5zxEa03KfAkSTpNFDZlI=;
b=T2uU4w0sg+QWu8OiJnmsLU0A6O6aALPLlhsQ4dQJraX+HuqM0Mm4bPSou8iiQyglMk
DX+21Aj2V2DEowPETCxAecsya2dprC/JIIJy6MRMxsTBzywAo+3VgJYU7n79440aqZE4
7z6KAeAzlXig0Cdvek1kcUbxFOZMT2GNgKRNc24AjPX4B4/fu1P5qZCXdJ2UF52CUNnK
WFF1UNUC6yVkQpNUqpbUIM1gO7aoqDtWy7szLhGfJWfrRXrXk33SW9AFuNHFdx6EEALh
WCZjxo//ETxAY0thP4d4KUoRmGvwEZGl2WKJLUJy+ARj8cTxAKh6KHGOm+khkIRn7hE5
aZqg==
X-Gm-Message-State: AOJu0YySHv34pf/PWBSAImoLzVyvKaaGJYC1OQLrsJAiK3d6SmVerJ0Z
Ii8XfaZ/83u+klTD8XGiBXhSdovMTHiZ5Cb26Q/3roLvAIcrQBY8xRC33bYPF7dDoGIrV9XKtUq
z
X-Gm-Gg: ASbGncvZpvoH3JpfTqoydYVet980zDypuXd829SPIeidvUcjnILFYfjrVWysqGI7LTo
Mb3qfy5CWidV+WvMw8TGdkSzUvt3pn/XOqk/O+VlNaTR/u9ALovnpT7vi1OTeG6A2ib4OUDbzV8
dEbSz5sp/i0DdgGOG6UF5sbKTP5iL0/xylCHPnAC6XUj3hABoTFm5Z2icPd1zNRW/17sOehXB78
1i19199t/quf1ZkzwuigHjz1rT6RWhh29cZjjWIqiiYwN8OjIpuV+Decwe6tYjSnbGkAVu3wWs+
ABUyDQ4DXxAKKRqq27dJjMHkgfjfNNTO81bmgpIWgGYFY0g2VJNqT3k=
X-Google-Smtp-Source: AGHT+IFiQWY6kNMY1tWvSK7dd62qgVrMgAJeucuOgAu92Dyk3jVbjXSomguV2t4pWqDLd3ZR2sNW0g==
X-Received: by 2002:a05:6a00:328b:b0:736:46b4:beef with SMTP id
d2e1a72fcca58-73dc147bc0bmr13735463b3a.3.1745202830433;
Sun, 20 Apr 2025 19:33:50 -0700 (PDT)
Received: from localhost ([2600:1700:65a7:3600:b90a:a0ba:c740:60a5])
by smtp.gmail.com with UTF8SMTPSA id
d2e1a72fcca58-73dbfaacf48sm5602174b3a.148.2025.04.20.19.33.49
(version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128);
Sun, 20 Apr 2025 19:33:50 -0700 (PDT)
From: Emma Worley <emma@emma.gg>
To: ffmpeg-devel@ffmpeg.org
Date: Sun, 20 Apr 2025 19:33:44 -0700
Message-ID: <20250421023345.7558-2-emma@emma.gg>
X-Mailer: git-send-email 2.48.0
In-Reply-To: <20250421023345.7558-1-emma@emma.gg>
References: <20250421023345.7558-1-emma@emma.gg>
MIME-Version: 1.0
Subject: [FFmpeg-devel] [PATCH v3 2/3] lavc/dxvenc: migrate DXT1 encoder to
lavu hashtable
X-BeenThere: ffmpeg-devel@ffmpeg.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: FFmpeg development discussions and patches <ffmpeg-devel.ffmpeg.org>
List-Unsubscribe: <https://ffmpeg.org/mailman/options/ffmpeg-devel>,
<mailto:ffmpeg-devel-request@ffmpeg.org?subject=unsubscribe>
List-Archive: <https://ffmpeg.org/pipermail/ffmpeg-devel>
List-Post: <mailto:ffmpeg-devel@ffmpeg.org>
List-Help: <mailto:ffmpeg-devel-request@ffmpeg.org?subject=help>
List-Subscribe: <https://ffmpeg.org/mailman/listinfo/ffmpeg-devel>,
<mailto:ffmpeg-devel-request@ffmpeg.org?subject=subscribe>
Reply-To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
Cc: Emma Worley <emma@emma.gg>
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Errors-To: ffmpeg-devel-bounces@ffmpeg.org
Sender: "ffmpeg-devel" <ffmpeg-devel-bounces@ffmpeg.org>
Archived-At: <https://master.gitmailbox.com/ffmpegdev/20250421023345.7558-2-emma@emma.gg/>
List-Archive: <https://master.gitmailbox.com/ffmpegdev/>
List-Post: <mailto:ffmpegdev@gitmailbox.com>
Offers a modest performance gain due to the switch from naive linear
probling to robin hood.
Signed-off-by: Emma Worley <emma@emma.gg>
---
libavcodec/dxvenc.c | 121 ++++++++++++--------------------------------
1 file changed, 33 insertions(+), 88 deletions(-)
diff --git a/libavcodec/dxvenc.c b/libavcodec/dxvenc.c
index 808d8daedb..c64b4d5f15 100644
--- a/libavcodec/dxvenc.c
+++ b/libavcodec/dxvenc.c
@@ -21,7 +21,7 @@
#include <stdint.h>
-#include "libavutil/crc.h"
+#include "libavutil/hashtable.h"
#include "libavutil/imgutils.h"
#include "libavutil/mem.h"
#include "libavutil/opt.h"
@@ -39,72 +39,9 @@
* appeared in the decompressed stream. Using a simple hash table (HT)
* significantly speeds up the lookback process while encoding.
*/
-#define LOOKBACK_HT_ELEMS 0x40000
+#define LOOKBACK_HT_ELEMS 0x20202
#define LOOKBACK_WORDS 0x20202
-typedef struct HTEntry {
- uint32_t key;
- uint32_t pos;
-} HTEntry;
-
-static void ht_init(HTEntry *ht)
-{
- for (size_t i = 0; i < LOOKBACK_HT_ELEMS; i++) {
- ht[i].pos = -1;
- }
-}
-
-static uint32_t ht_lookup_and_upsert(HTEntry *ht, const AVCRC *hash_ctx,
- uint32_t key, uint32_t pos)
-{
- uint32_t ret = -1;
- size_t hash = av_crc(hash_ctx, 0, (uint8_t*)&key, 4) % LOOKBACK_HT_ELEMS;
- for (size_t i = hash; i < hash + LOOKBACK_HT_ELEMS; i++) {
- size_t wrapped_index = i % LOOKBACK_HT_ELEMS;
- HTEntry *entry = &ht[wrapped_index];
- if (entry->key == key || entry->pos == -1) {
- ret = entry->pos;
- entry->key = key;
- entry->pos = pos;
- break;
- }
- }
- return ret;
-}
-
-static void ht_delete(HTEntry *ht, const AVCRC *hash_ctx,
- uint32_t key, uint32_t pos)
-{
- HTEntry *removed_entry = NULL;
- size_t removed_hash;
- size_t hash = av_crc(hash_ctx, 0, (uint8_t*)&key, 4) % LOOKBACK_HT_ELEMS;
-
- for (size_t i = hash; i < hash + LOOKBACK_HT_ELEMS; i++) {
- size_t wrapped_index = i % LOOKBACK_HT_ELEMS;
- HTEntry *entry = &ht[wrapped_index];
- if (entry->pos == -1)
- return;
- if (removed_entry) {
- size_t candidate_hash = av_crc(hash_ctx, 0, (uint8_t*)&entry->key, 4) % LOOKBACK_HT_ELEMS;
- if ((wrapped_index > removed_hash && (candidate_hash <= removed_hash || candidate_hash > wrapped_index)) ||
- (wrapped_index < removed_hash && (candidate_hash <= removed_hash && candidate_hash > wrapped_index))) {
- *removed_entry = *entry;
- entry->pos = -1;
- removed_entry = entry;
- removed_hash = wrapped_index;
- }
- } else if (entry->key == key) {
- if (entry->pos <= pos) {
- entry->pos = -1;
- removed_entry = entry;
- removed_hash = wrapped_index;
- } else {
- return;
- }
- }
- }
-}
-
typedef struct DXVEncContext {
AVClass *class;
@@ -121,10 +58,8 @@ typedef struct DXVEncContext {
DXVTextureFormat tex_fmt;
int (*compress_tex)(AVCodecContext *avctx);
- const AVCRC *crc_ctx;
-
- HTEntry color_lookback_ht[LOOKBACK_HT_ELEMS];
- HTEntry lut_lookback_ht[LOOKBACK_HT_ELEMS];
+ struct AVHashtableContext *color_ht;
+ struct AVHashtableContext *lut_ht;
} DXVEncContext;
/* Converts an index offset value to a 2-bit opcode and pushes it to a stream.
@@ -159,27 +94,32 @@ static int dxv_compress_dxt1(AVCodecContext *avctx)
DXVEncContext *ctx = avctx->priv_data;
PutByteContext *pbc = &ctx->pbc;
void *value;
- uint32_t color, lut, idx, color_idx, lut_idx, prev_pos, state = 16, pos = 2, op = 0;
+ uint32_t color, lut, idx, color_idx, lut_idx, prev_pos, state = 16, pos = 0, op = 0;
- ht_init(ctx->color_lookback_ht);
- ht_init(ctx->lut_lookback_ht);
+ av_hashtable_clear(ctx->color_ht);
+ av_hashtable_clear(ctx->lut_ht);
bytestream2_put_le32(pbc, AV_RL32(ctx->tex_data));
+ av_hashtable_set(ctx->color_ht, ctx->tex_data, &pos);
+ pos++;
bytestream2_put_le32(pbc, AV_RL32(ctx->tex_data + 4));
-
- ht_lookup_and_upsert(ctx->color_lookback_ht, ctx->crc_ctx, AV_RL32(ctx->tex_data), 0);
- ht_lookup_and_upsert(ctx->lut_lookback_ht, ctx->crc_ctx, AV_RL32(ctx->tex_data + 4), 1);
+ av_hashtable_set(ctx->lut_ht, ctx->tex_data + 4, &pos);
+ pos++;
while (pos + 2 <= ctx->tex_size / 4) {
idx = 0;
+ color_idx = 0;
+ lut_idx = 0;
color = AV_RL32(ctx->tex_data + pos * 4);
- prev_pos = ht_lookup_and_upsert(ctx->color_lookback_ht, ctx->crc_ctx, color, pos);
- color_idx = prev_pos != -1 ? pos - prev_pos : 0;
+ if (av_hashtable_get(ctx->color_ht, &color, &prev_pos))
+ color_idx = pos - prev_pos;
+ av_hashtable_set(ctx->color_ht, &color, &pos);
+
if (pos >= LOOKBACK_WORDS) {
uint32_t old_pos = pos - LOOKBACK_WORDS;
- uint32_t old_color = AV_RL32(ctx->tex_data + old_pos * 4);
- ht_delete(ctx->color_lookback_ht, ctx->crc_ctx, old_color, old_pos);
+ if (av_hashtable_get(ctx->color_ht, ctx->tex_data + old_pos * 4, &prev_pos) && prev_pos <= old_pos)
+ av_hashtable_delete(ctx->color_ht, ctx->tex_data + old_pos * 4);
}
pos++;
@@ -188,13 +128,14 @@ static int dxv_compress_dxt1(AVCodecContext *avctx)
idx = color_idx;
} else {
idx = 0;
- prev_pos = ht_lookup_and_upsert(ctx->lut_lookback_ht, ctx->crc_ctx, lut, pos);
- lut_idx = prev_pos != -1 ? pos - prev_pos : 0;
+ if (av_hashtable_get(ctx->lut_ht, &lut, &prev_pos))
+ lut_idx = pos - prev_pos;
+ av_hashtable_set(ctx->lut_ht, &lut, &pos);
}
if (pos >= LOOKBACK_WORDS) {
uint32_t old_pos = pos - LOOKBACK_WORDS;
- uint32_t old_lut = AV_RL32(ctx->tex_data + old_pos * 4);
- ht_delete(ctx->lut_lookback_ht, ctx->crc_ctx, old_lut, old_pos);
+ if (av_hashtable_get(ctx->lut_ht, ctx->tex_data + old_pos * 4, &prev_pos) && prev_pos <= old_pos)
+ av_hashtable_delete(ctx->lut_ht, ctx->tex_data + old_pos * 4);
}
pos++;
@@ -306,11 +247,12 @@ static av_cold int dxv_init(AVCodecContext *avctx)
return AVERROR(ENOMEM);
}
- ctx->crc_ctx = av_crc_get_table(AV_CRC_32_IEEE);
- if (!ctx->crc_ctx) {
- av_log(avctx, AV_LOG_ERROR, "Could not initialize CRC table.\n");
- return AVERROR_BUG;
- }
+ ret = av_hashtable_alloc(&ctx->color_ht, sizeof(uint32_t), sizeof(uint32_t), LOOKBACK_HT_ELEMS);
+ if (ret < 0)
+ return ret;
+ ret = av_hashtable_alloc(&ctx->lut_ht, sizeof(uint32_t), sizeof(uint32_t), LOOKBACK_HT_ELEMS);
+ if (ret < 0)
+ return ret;
return 0;
}
@@ -321,6 +263,9 @@ static av_cold int dxv_close(AVCodecContext *avctx)
av_freep(&ctx->tex_data);
+ av_hashtable_freep(&ctx->color_ht);
+ av_hashtable_freep(&ctx->lut_ht);
+
return 0;
}
--
2.48.0
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".