From 4f7aeffd8c3607aea6464a20eba4cc9106173c52 Mon Sep 17 00:00:00 2001 From: Ramiro Polla Date: Thu, 22 Aug 2024 01:24:54 +0200 Subject: [PATCH] avcodec/mpegvideo: remove redundant workaround to recalculate last nonzero coefficient The x86 optimized dct_quantize only calculates the last nonzero coefficient correctly if the zigzag scan order is used. For the alternate scan order, this value is incorrect. To work around this, the dct_unquantize functions process the entire block if the alternate scan order is used. But a second workaround (bb198e198ab) was added that recalculates the last nonzero coefficient after dct_quantize is called if the alternate scan order is used. This commit removes the first workaround, which became redundant. --- libavcodec/mpegvideo.c | 9 +++------ libavcodec/x86/mpegvideo.c | 6 ++---- 2 files changed, 5 insertions(+), 10 deletions(-) diff --git a/libavcodec/mpegvideo.c b/libavcodec/mpegvideo.c index b9a0469335..01e310e483 100644 --- a/libavcodec/mpegvideo.c +++ b/libavcodec/mpegvideo.c @@ -110,8 +110,7 @@ static void dct_unquantize_mpeg2_intra_c(MpegEncContext *s, if (s->q_scale_type) qscale = ff_mpeg2_non_linear_qscale[qscale]; else qscale <<= 1; - if(s->alternate_scan) nCoeffs= 63; - else nCoeffs= s->block_last_index[n]; + nCoeffs= s->block_last_index[n]; block[0] *= n < 4 ? s->y_dc_scale : s->c_dc_scale; quant_matrix = s->intra_matrix; @@ -141,8 +140,7 @@ static void dct_unquantize_mpeg2_intra_bitexact(MpegEncContext *s, if (s->q_scale_type) qscale = ff_mpeg2_non_linear_qscale[qscale]; else qscale <<= 1; - if(s->alternate_scan) nCoeffs= 63; - else nCoeffs= s->block_last_index[n]; + nCoeffs= s->block_last_index[n]; block[0] *= n < 4 ? s->y_dc_scale : s->c_dc_scale; sum += block[0]; @@ -175,8 +173,7 @@ static void dct_unquantize_mpeg2_inter_c(MpegEncContext *s, if (s->q_scale_type) qscale = ff_mpeg2_non_linear_qscale[qscale]; else qscale <<= 1; - if(s->alternate_scan) nCoeffs= 63; - else nCoeffs= s->block_last_index[n]; + nCoeffs= s->block_last_index[n]; quant_matrix = s->inter_matrix; for(i=0; i<=nCoeffs; i++) { diff --git a/libavcodec/x86/mpegvideo.c b/libavcodec/x86/mpegvideo.c index 73967cafda..9878607a81 100644 --- a/libavcodec/x86/mpegvideo.c +++ b/libavcodec/x86/mpegvideo.c @@ -312,8 +312,7 @@ static void dct_unquantize_mpeg2_intra_mmx(MpegEncContext *s, if (s->q_scale_type) qscale = ff_mpeg2_non_linear_qscale[qscale]; else qscale <<= 1; - if(s->alternate_scan) nCoeffs= 63; //FIXME - else nCoeffs= s->intra_scantable.raster_end[ s->block_last_index[n] ]; + nCoeffs= s->intra_scantable.raster_end[ s->block_last_index[n] ]; if (n < 4) block0 = block[0] * s->y_dc_scale; @@ -380,8 +379,7 @@ static void dct_unquantize_mpeg2_inter_mmx(MpegEncContext *s, if (s->q_scale_type) qscale = ff_mpeg2_non_linear_qscale[qscale]; else qscale <<= 1; - if(s->alternate_scan) nCoeffs= 63; //FIXME - else nCoeffs= s->intra_scantable.raster_end[ s->block_last_index[n] ]; + nCoeffs= s->intra_scantable.raster_end[ s->block_last_index[n] ]; quant_matrix = s->inter_matrix; __asm__ volatile(