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jpegdepay: store quant tables in zigzag order

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This commit is contained in:
Wim Taymans 2012-10-17 14:23:01 +02:00
parent d5fd524a0c
commit e9040e90a5
1 changed files with 13 additions and 2 deletions
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15
gst/rtp/gstrtpjpegdepay.c
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@ -154,6 +154,17 @@ gst_rtp_jpeg_depay_finalize (GObject * object)
G_OBJECT_CLASS (parent_class)->finalize (object); G_OBJECT_CLASS (parent_class)->finalize (object);
} }
static const int zigzag[] = {
0, 1, 8, 16, 9, 2, 3, 10,
17, 24, 32, 25, 18, 11, 4, 5,
12, 19, 26, 33, 40, 48, 41, 34,
27, 20, 13, 6, 7, 14, 21, 28,
35, 42, 49, 56, 57, 50, 43, 36,
29, 22, 15, 23, 30, 37, 44, 51,
58, 59, 52, 45, 38, 31, 39, 46,
53, 60, 61, 54, 47, 55, 62, 63
};
/* /*
* Table K.1 from JPEG spec. * Table K.1 from JPEG spec.
*/ */
@ -198,8 +209,8 @@ MakeTables (GstRtpJPEGDepay * rtpjpegdepay, gint Q, guint8 qtable[128])
Q = 200 - factor * 2; Q = 200 - factor * 2;
for (i = 0; i < 64; i++) { for (i = 0; i < 64; i++) {
gint lq = (jpeg_luma_quantizer[i] * Q + 50) / 100; gint lq = (jpeg_luma_quantizer[zigzag[i]] * Q + 50) / 100;
gint cq = (jpeg_chroma_quantizer[i] * Q + 50) / 100; gint cq = (jpeg_chroma_quantizer[zigzag[i]] * Q + 50) / 100;
/* Limit the quantizers to 1 <= q <= 255 */ /* Limit the quantizers to 1 <= q <= 255 */
qtable[i] = CLAMP (lq, 1, 255); qtable[i] = CLAMP (lq, 1, 255);