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mpeg2: fix slice_horizontal_position calculation.

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This commit is contained in:
Gwenole Beauchesne 2012-02-23 14:17:34 +01:00
parent b36d2c810e
commit 60e515e0b7
1 changed files with 103 additions and 3 deletions
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106
gst-libs/gst/vaapi/gstvaapidecoder_mpeg2.c
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@ -53,6 +53,13 @@ G_DEFINE_TYPE(GstVaapiDecoderMpeg2,
} \
} G_STMT_END
#define SKIP(reader, nbits) G_STMT_START { \
if (!gst_bit_reader_skip (reader, nbits)) { \
GST_WARNING ("failed to skip nbits: %d", nbits); \
goto failed; \
} \
} G_STMT_END
struct _GstVaapiDecoderMpeg2Private {
GstVaapiProfile profile;
guint width;
@ -86,6 +93,85 @@ struct _GstVaapiDecoderMpeg2Private {
guint broken_link : 1;
};
/* VLC decoder from gst-plugins-bad */
typedef struct _VLCTable VLCTable;
struct _VLCTable {
gint value;
guint cword;
guint cbits;
};
static gboolean
decode_vlc(GstBitReader *br, gint *res, const VLCTable *table, guint length)
{
guint8 i;
guint cbits = 0;
guint32 value = 0;
for (i = 0; i < length; i++) {
if (cbits != table[i].cbits) {
cbits = table[i].cbits;
if (!gst_bit_reader_peek_bits_uint32(br, &value, cbits)) {
goto failed;
}
}
if (value == table[i].cword) {
SKIP(br, cbits);
if (res)
*res = table[i].value;
return TRUE;
}
}
GST_DEBUG("failed to find VLC code");
failed:
GST_WARNING("failed to decode VLC, returning");
return FALSE;
}
enum {
GST_MPEG_VIDEO_MACROBLOCK_ESCAPE = -1,
};
/* Table B-1: Variable length codes for macroblock_address_increment */
static const VLCTable mpeg2_mbaddr_vlc_table[] = {
{ 1, 0x01, 1 },
{ 2, 0x03, 3 },
{ 3, 0x02, 3 },
{ 4, 0x03, 4 },
{ 5, 0x02, 4 },
{ 6, 0x03, 5 },
{ 7, 0x02, 5 },
{ 8, 0x07, 7 },
{ 9, 0x06, 7 },
{ 10, 0x0b, 8 },
{ 11, 0x0a, 8 },
{ 12, 0x09, 8 },
{ 13, 0x08, 8 },
{ 14, 0x07, 8 },
{ 15, 0x06, 8 },
{ 16, 0x17, 10 },
{ 17, 0x16, 10 },
{ 18, 0x15, 10 },
{ 19, 0x14, 10 },
{ 20, 0x13, 10 },
{ 21, 0x12, 10 },
{ 22, 0x23, 11 },
{ 23, 0x22, 11 },
{ 24, 0x21, 11 },
{ 25, 0x20, 11 },
{ 26, 0x1f, 11 },
{ 27, 0x1e, 11 },
{ 28, 0x1d, 11 },
{ 29, 0x1c, 11 },
{ 30, 0x1b, 11 },
{ 31, 0x1a, 11 },
{ 32, 0x19, 11 },
{ 33, 0x18, 11 },
{ GST_MPEG_VIDEO_MACROBLOCK_ESCAPE, 0x08, 11 }
};
static void
gst_vaapi_decoder_mpeg2_close(GstVaapiDecoderMpeg2 *decoder)
{
@ -569,6 +655,8 @@ decode_slice(
GstVaapiSlice *slice;
VASliceParameterBufferMPEG2 *slice_param;
GstBitReader br;
gint mb_x, mb_y, mb_inc;
guint macroblock_offset;
guint8 slice_vertical_position_extension;
guint8 quantiser_scale_code;
guint8 intra_slice_flag, intra_slice = 0;
@ -613,12 +701,24 @@ decode_slice(
READ_UINT8(&br, extra_bit_slice, 1);
}
}
macroblock_offset = gst_bit_reader_get_pos(&br);
mb_y = slice_no;
mb_x = -1;
do {
if (!decode_vlc(&br, &mb_inc, mpeg2_mbaddr_vlc_table,
G_N_ELEMENTS(mpeg2_mbaddr_vlc_table))) {
GST_WARNING("failed to decode first macroblock_address_increment");
goto failed;
}
mb_x += mb_inc == GST_MPEG_VIDEO_MACROBLOCK_ESCAPE ? 33 : mb_inc;
} while (mb_inc == GST_MPEG_VIDEO_MACROBLOCK_ESCAPE);
/* Fill in VASliceParameterBufferMPEG2 */
slice_param = slice->param;
slice_param->macroblock_offset = gst_bit_reader_get_pos(&br);
slice_param->slice_horizontal_position = 0;
slice_param->slice_vertical_position = slice_no;
slice_param->macroblock_offset = macroblock_offset;
slice_param->slice_horizontal_position = mb_x;
slice_param->slice_vertical_position = mb_y;
slice_param->quantiser_scale_code = quantiser_scale_code;
slice_param->intra_slice_flag = intra_slice;
return GST_VAAPI_DECODER_STATUS_SUCCESS;