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avcodec/mpeg12dec: Don't initialize unused parts of ScanTable

The MPEG-1/2 decoders don't need ScanTable.raster_end (as the coefficients are unquantized as they are parsed).

Andreas Rheinhardt committed 1 year ago

Commit 79d66571 parent e6657d41 file · +7 −6Browse files

Showing the changes to libavcodec (1 of 1 file). Show all

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libavcodec/mpeg12dec.c+7−6
@@ -1228,10 +1228,10 @@ static int mpeg_decode_picture_coding_extension(Mpeg1Context *s1) · 1227 unmodified lines
12281228 s->chroma_420_type = get_bits1(&s->gb);
12291229 s->progressive_frame = get_bits1(&s->gb);
12301230
1231− // We only initialize intra_scantable, as both scantables always coincide
1232− // and all code therefore only uses the intra one.
1233− ff_init_scantable(s->idsp.idct_permutation, &s->intra_scantable,
1234− s->alternate_scan ? ff_alternate_vertical_scan : ff_zigzag_direct);
1231+ // We only initialize intra_scantable.permutated, as this is all we use.
1232+ ff_permute_scantable(s->intra_scantable.permutated,
1233+ s->alternate_scan ? ff_alternate_vertical_scan : ff_zigzag_direct,
1234+ s->idsp.idct_permutation);
12351235
12361236 /* composite display not parsed */
12371237 ff_dlog(s->avctx, "intra_dc_precision=%d\n", s->intra_dc_precision);
@@ -2803,8 +2803,9 @@ static int ipu_decode_frame(AVCodecContext *avctx, AVFrame *frame, · 1565 unmodified lines
28032803 m->intra_vlc_format = !!(s->flags & 0x20);
28042804 m->alternate_scan = !!(s->flags & 0x10);
28052805
2806− ff_init_scantable(m->idsp.idct_permutation, &m->intra_scantable,
2807− s->flags & 0x10 ? ff_alternate_vertical_scan : ff_zigzag_direct);
2806+ ff_permute_scantable(m->intra_scantable.permutated,
2807+ s->flags & 0x10 ? ff_alternate_vertical_scan : ff_zigzag_direct,
2808+ m->idsp.idct_permutation);
28082809
28092810 m->last_dc[0] = m->last_dc[1] = m->last_dc[2] = 1 << (7 + (s->flags & 3));
28102811 m->qscale = 1;

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