From 88d80cb97528d52dac3178cf5393d6095eca6200 Mon Sep 17 00:00:00 2001 From: "Steinar H. Gunderson" Date: Sat, 18 Jul 2020 16:53:03 +0200 Subject: [PATCH] avcodec/put_bits: Make bit buffers 64-bit Change BitBuf into uint64_t on 64-bit x86. This means we need to flush the buffer less often, which is a significant speed win. All other platforms, including all 32-bit ones, are unchanged. Output bitstream is the same. All API constraints are kept in place, e.g., you still cannot put_bits() more than 31 bits at a time. This is so that codecs cannot accidentally become 64-bit-only or similar. Benchmarking on transcoding to various formats shows consistently positive results: dnxhd 25.60 fps -> 26.26 fps ( +2.6%) dvvideo 24.88 fps -> 25.17 fps ( +1.2%) ffv1 14.32 fps -> 14.58 fps ( +1.8%) huffyuv 58.75 fps -> 63.27 fps ( +7.7%) jpegls 6.22 fps -> 6.34 fps ( +1.8%) magicyuv 57.10 fps -> 63.29 fps (+10.8%) mjpeg 48.65 fps -> 49.01 fps ( +0.7%) mpeg1video 76.41 fps -> 77.01 fps ( +0.8%) mpeg2video 75.99 fps -> 77.43 fps ( +1.9%) mpeg4 80.66 fps -> 81.37 fps ( +0.9%) prores 12.35 fps -> 12.88 fps ( +4.3%) prores_ks 16.20 fps -> 16.80 fps ( +3.7%) rv20 62.80 fps -> 62.99 fps ( +0.3%) utvideo 68.41 fps -> 76.32 fps (+11.6%) Note that this includes video decoding and all other encoding work, such as DCTs. If you isolate the actual bit-writing routines, it is likely to be much more. Benchmark details: Transcoding the first 30 seconds of Big Buck Bunny in 1080p, Haswell 2.1 GHz, GCC 8.3, generally quantizer locked to 5.0. (Exceptions: DNxHD needs fixed bitrate, and JPEG-LS is so slow that I only took the first 10 seconds, not 30.) All runs were done ten times and single-threaded, top and bottom two results discarded to get rid of outliers, arithmetic mean between the remaining six. Signed-off-by: Michael Niedermayer --- libavcodec/asvenc.c | 1 + libavcodec/put_bits.h | 31 ++++++++++++++++++++++++------- 2 files changed, 25 insertions(+), 7 deletions(-) diff --git a/libavcodec/asvenc.c b/libavcodec/asvenc.c index c2c940f365..28f7a94071 100644 --- a/libavcodec/asvenc.c +++ b/libavcodec/asvenc.c @@ -295,6 +295,7 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt, while (put_bits_count(&a->pb) & 31) put_bits(&a->pb, 8, 0); + flush_put_bits(&a->pb); size = put_bits_count(&a->pb) / 32; if (avctx->codec_id == AV_CODEC_ID_ASV1) { diff --git a/libavcodec/put_bits.h b/libavcodec/put_bits.h index c6a8f3ac14..ddd97906b2 100644 --- a/libavcodec/put_bits.h +++ b/libavcodec/put_bits.h @@ -29,12 +29,20 @@ #include #include +#include "config.h" #include "libavutil/intreadwrite.h" #include "libavutil/avassert.h" +#if ARCH_X86_64 +// TODO: Benchmark and optionally enable on other 64-bit architectures. +typedef uint64_t BitBuf; +#define AV_WBBUF AV_WB64 +#define AV_WLBUF AV_WL64 +#else typedef uint32_t BitBuf; #define AV_WBBUF AV_WB32 #define AV_WLBUF AV_WL32 +#endif static const int BUF_BITS = 8 * sizeof(BitBuf); @@ -163,17 +171,11 @@ void avpriv_put_string(PutBitContext *pb, const char *string, void avpriv_copy_bits(PutBitContext *pb, const uint8_t *src, int length); #endif -/** - * Write up to 31 bits into a bitstream. - * Use put_bits32 to write 32 bits. - */ -static inline void put_bits(PutBitContext *s, int n, BitBuf value) +static inline void put_bits_no_assert(PutBitContext *s, int n, BitBuf value) { BitBuf bit_buf; int bit_left; - av_assert2(n <= 31 && value < (1UL << n)); - bit_buf = s->bit_buf; bit_left = s->bit_left; @@ -215,6 +217,16 @@ static inline void put_bits(PutBitContext *s, int n, BitBuf value) s->bit_left = bit_left; } +/** + * Write up to 31 bits into a bitstream. + * Use put_bits32 to write 32 bits. + */ +static inline void put_bits(PutBitContext *s, int n, BitBuf value) +{ + av_assert2(n <= 31 && value < (1UL << n)); + put_bits_no_assert(s, n, value); +} + static inline void put_bits_le(PutBitContext *s, int n, BitBuf value) { BitBuf bit_buf; @@ -258,6 +270,11 @@ static void av_unused put_bits32(PutBitContext *s, uint32_t value) BitBuf bit_buf; int bit_left; + if (BUF_BITS > 32) { + put_bits_no_assert(s, 32, value); + return; + } + bit_buf = s->bit_buf; bit_left = s->bit_left;