On Fri, 8 Mar 2024, Andreas Rheinhardt wrote:
Andreas Rheinhardt:Use a small LUT instead. Improves performance. Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@outlook.com> --- libavcodec/xbmenc.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/libavcodec/xbmenc.c b/libavcodec/xbmenc.c index cd8b73afa3..5231d4691d 100644 --- a/libavcodec/xbmenc.c +++ b/libavcodec/xbmenc.c @@ -20,11 +20,9 @@ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ -#include "libavutil/reverse.h" #include "avcodec.h" #include "codec_internal.h" #include "encode.h" -#include "mathops.h" #define ANSI_MIN_READLINE 509 @@ -57,14 +55,25 @@ static int xbm_encode_frame(AVCodecContext *avctx, AVPacket *pkt, buf += snprintf(buf, 39, "static unsigned char image_bits[] = {\n"); for (i = 0, l = lineout; i < avctx->height; i++) { for (j = 0; j < linesize; j++) { - buf += snprintf(buf, 6, " 0x%02X", ff_reverse[*ptr++]); + // 0..15 bitreversed as chars + static const char lut[] = { + '0', '8', '4', 'C', '2', 'A', '6', 'E', + '1', '9', '5', 'D', '3', 'B', '7', 'F' + }; + buf[0] = ' '; + buf[1] = '0'; + buf[2] = 'x'; + buf[3] = lut[*ptr & 0xF]; + buf[4] = lut[*ptr >> 4];
Maybe you could use *buf++ = ... here as well, to avoid the next line. But fine either way I guess.
Thanks, Marton
+ buf += 5; + ptr++; if (--commas <= 0) { - buf += snprintf(buf, 2, "\n"); + *buf++ = '\n'; break; } - buf += snprintf(buf, 2, ","); + *buf++ = ','; if (--l <= 0) { - buf += snprintf(buf, 2, "\n"); + *buf++ = '\n'; l = lineout; } }Will apply this patch tomorrow unless there are objections. - Andreas _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
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