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mpeg2: parse slice() header earlier.

Browse source 
Parse slice() header and first macroblock position earlier in _parse()
function instead of waiting for the _decode() stage. This doesn't change
anything but readability.
This commit is contained in:
Gwenole Beauchesne 2012-12-27 14:54:29 +01:00
parent 549b5a9389
commit 4a39efa9f6
1 changed files with 78 additions and 50 deletions
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128
gst-libs/gst/vaapi/gstvaapidecoder_mpeg2.c
View file

@ -171,6 +171,17 @@ pts_eval(PTSGenerator *tsg, GstClockTime pic_pts, guint pic_tsn)
/* --- MPEG-2 Decoder Units --- */
/* ------------------------------------------------------------------------- */
typedef struct _GstMpegVideoSliceHdr GstMpegVideoSliceHdr;
struct _GstMpegVideoSliceHdr {
guint16 slice_horizontal_position;
guint16 slice_vertical_position;
guint8 quantiser_scale_code;
guint8 intra_slice;
/* Size of the slice() header in bits */
guint header_size;
};
typedef struct _GstVaapiDecoderUnitMpeg2 GstVaapiDecoderUnitMpeg2;
struct _GstVaapiDecoderUnitMpeg2 {
GstVaapiDecoderUnit base;
@ -183,6 +194,7 @@ struct _GstVaapiDecoderUnitMpeg2 {
GstMpegVideoQuantMatrixExt quant_matrix;
GstMpegVideoPictureHdr pic_hdr;
GstMpegVideoPictureExt pic_ext;
GstMpegVideoSliceHdr slice_hdr;
} data;
};
@ -733,6 +745,58 @@ parse_picture(GstVaapiDecoderUnitMpeg2 *unit)
return GST_VAAPI_DECODER_STATUS_SUCCESS;
}
static GstVaapiDecoderStatus
parse_slice(GstVaapiDecoderMpeg2 *decoder, GstVaapiDecoderUnitMpeg2 *unit)
{
GstVaapiDecoderMpeg2Private * const priv = decoder->priv;
GstMpegVideoSliceHdr * const slice_hdr = &unit->data.slice_hdr;
GstMpegVideoPacket * const packet = &unit->packet;
GstBitReader br;
gint mb_x, mb_y, mb_inc;
guint8 slice_vertical_position_extension;
guint8 extra_bit_slice, junk8;
gst_bit_reader_init(&br, packet->data + packet->offset, packet->size);
if (priv->height > 2800)
READ_UINT8(&br, slice_vertical_position_extension, 3);
if (priv->has_seq_scalable_ext) {
GST_ERROR("failed to parse slice with sequence_scalable_extension()");
return GST_VAAPI_DECODER_STATUS_ERROR_BITSTREAM_PARSER;
}
READ_UINT8(&br, slice_hdr->quantiser_scale_code, 5);
READ_UINT8(&br, extra_bit_slice, 1);
if (!extra_bit_slice)
slice_hdr->intra_slice = 0;
else {
READ_UINT8(&br, slice_hdr->intra_slice, 1);
READ_UINT8(&br, junk8, 7);
READ_UINT8(&br, extra_bit_slice, 1);
while (extra_bit_slice) {
READ_UINT8(&br, junk8, 8);
READ_UINT8(&br, extra_bit_slice, 1);
}
}
slice_hdr->header_size = 32 + gst_bit_reader_get_pos(&br);
mb_y = packet->type - GST_MPEG_VIDEO_PACKET_SLICE_MIN;
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);
slice_hdr->slice_horizontal_position = mb_x;
slice_hdr->slice_vertical_position = mb_y;
return GST_VAAPI_DECODER_STATUS_SUCCESS;
failed:
return GST_VAAPI_DECODER_STATUS_ERROR_BITSTREAM_PARSER;
}
static GstVaapiDecoderStatus
decode_picture(GstVaapiDecoderMpeg2 *decoder, GstVaapiDecoderUnitMpeg2 *unit)
{
@ -970,16 +1034,10 @@ decode_slice(GstVaapiDecoderMpeg2 *decoder, GstVaapiDecoderUnitMpeg2 *unit)
GstVaapiSlice *slice;
VASliceParameterBufferMPEG2 *slice_param;
GstMpegVideoPacket * const packet = &unit->packet;
const gint slice_no = packet->type - GST_MPEG_VIDEO_PACKET_SLICE_MIN;
GstBitReader br;
gint mb_x, mb_y, mb_inc;
guint macroblock_offset;
guint8 slice_vertical_position_extension;
guint8 quantiser_scale_code;
guint8 intra_slice = 0;
guint8 extra_bit_slice, junk8;
GstMpegVideoSliceHdr * const slice_hdr = &unit->data.slice_hdr;
GST_DEBUG("slice %d (%u bytes)", slice_no, packet->size);
GST_DEBUG("slice %d (%u bytes)", slice_hdr->slice_vertical_position,
packet->size);
if (!picture)
return GST_VAAPI_DECODER_STATUS_SUCCESS;
@ -1003,50 +1061,14 @@ decode_slice(GstVaapiDecoderMpeg2 *decoder, GstVaapiDecoderUnitMpeg2 *unit)
}
gst_vaapi_picture_add_slice(picture, slice);
/* Parse slice */
gst_bit_reader_init(&br, GST_BUFFER_DATA(unit->base.buffer), packet->size);
SKIP(&br, 32); /* slice_start_code */
if (priv->height > 2800)
READ_UINT8(&br, slice_vertical_position_extension, 3);
if (priv->has_seq_scalable_ext) {
GST_ERROR("failed to parse slice %d. Unsupported sequence_scalable_extension()", slice_no);
return GST_VAAPI_DECODER_STATUS_ERROR_BITSTREAM_PARSER;
}
READ_UINT8(&br, quantiser_scale_code, 5);
READ_UINT8(&br, extra_bit_slice, 1);
if (extra_bit_slice == 1) {
READ_UINT8(&br, intra_slice, 1);
READ_UINT8(&br, junk8, 7);
READ_UINT8(&br, extra_bit_slice, 1);
while (extra_bit_slice == 1) {
READ_UINT8(&br, junk8, 8);
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 = 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;
slice_param->macroblock_offset = slice_hdr->header_size;
slice_param->slice_horizontal_position = slice_hdr->slice_horizontal_position;
slice_param->slice_vertical_position = slice_hdr->slice_vertical_position;
slice_param->quantiser_scale_code = slice_hdr->quantiser_scale_code;
slice_param->intra_slice_flag = slice_hdr->intra_slice;
return GST_VAAPI_DECODER_STATUS_SUCCESS;
failed:
return GST_VAAPI_DECODER_STATUS_ERROR_BITSTREAM_PARSER;
}
static inline gint
@ -1221,6 +1243,12 @@ gst_vaapi_decoder_mpeg2_parse(GstVaapiDecoder *base_decoder,
}
break;
default:
if (packet->type >= GST_MPEG_VIDEO_PACKET_SLICE_MIN &&
packet->type <= GST_MPEG_VIDEO_PACKET_SLICE_MAX) {
status = parse_slice(decoder, unit);
break;
}
status = GST_VAAPI_DECODER_STATUS_SUCCESS;
break;
}