[FFmpeg-cvslog] Implement lms_update()
Mashiat Sarker Shakkhar
git at videolan.org
Fri Nov 11 03:42:40 CET 2011
ffmpeg | branch: master | Mashiat Sarker Shakkhar <shahriman_ams at yahoo.com> | Sun Nov 6 03:02:41 2011 +0600| [80fa79a306c6be1dd4ed0fb4df8c582bb2f74fe5] | committer: Michael Niedermayer
Implement lms_update()
(cherry picked from commit 17219c79360bc2bdaf3e7f47178af42fade140a8)
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=80fa79a306c6be1dd4ed0fb4df8c582bb2f74fe5
---
libavcodec/wmalosslessdec.c | 49 +++++++++++++++++++++++++++++++++++++++++++
1 files changed, 49 insertions(+), 0 deletions(-)
diff --git a/libavcodec/wmalosslessdec.c b/libavcodec/wmalosslessdec.c
index 8f7f290..a6c6365 100644
--- a/libavcodec/wmalosslessdec.c
+++ b/libavcodec/wmalosslessdec.c
@@ -774,6 +774,55 @@ static int lms_predict(WmallDecodeCtx *s, int ich, int ilms)
return pred;
}
+static void lms_update(WmallDecodeCtx *s, int ich, int ilms, int32_t input, int32_t pred)
+{
+ int icoef;
+ int recent = s->cdlms[ich][ilms].recent;
+ int range = 1 << (s->bits_per_sample - 1);
+ int bps = s->bits_per_sample > 16 ? 4 : 2; // bytes per sample
+
+ if (input > pred) {
+ for (icoef = 0; icoef < s->cdlms[ich][ilms].order; icoef++)
+ s->cdlms[ich][ilms].coefs[icoef] +=
+ s->cdlms[ich][ilms].lms_updates[icoef + recent];
+ } else {
+ for (icoef = 0; icoef < s->cdlms[ich][ilms].order; icoef++)
+ s->cdlms[ich][ilms].coefs[icoef] -=
+ s->cdlms[ich][ilms].lms_updates[icoef]; // XXX: [icoef + recent] ?
+ }
+ s->cdlms[ich][ilms].recent--;
+ s->cdlms[ich][ilms].lms_prevvalues[recent] = av_clip(input, -range, range - 1);
+
+ if (input > pred)
+ s->cdlms[ich][ilms].lms_updates[recent] = s->update_speed[ich];
+ else if (input < pred)
+ s->cdlms[ich][ilms].lms_updates[recent] = -s->update_speed[ich];
+
+ /* XXX: spec says:
+ cdlms[iCh][ilms].updates[iRecent + cdlms[iCh][ilms].order >> 4] >>= 2;
+ lms_updates[iCh][ilms][iRecent + cdlms[iCh][ilms].order >> 3] >>= 1;
+
+ Questions is - are cdlms[iCh][ilms].updates[] and lms_updates[][][] two
+ seperate buffers? Here I've assumed that the two are same which makes
+ more sense to me.
+ */
+ s->cdlms[ich][ilms].lms_updates[recent + s->cdlms[ich][ilms].order >> 4] >>= 2;
+ s->cdlms[ich][ilms].lms_updates[recent + s->cdlms[ich][ilms].order >> 3] >>= 1;
+ /* XXX: recent + (s->cdlms[ich][ilms].order >> 4) ? */
+
+ if (s->cdlms[ich][ilms].recent == 0) {
+ /* XXX: This memcpy()s will probably fail if a fixed 32-bit buffer is used.
+ follow kshishkov's suggestion of using a union. */
+ memcpy(s->cdlms[ich][ilms].lms_prevvalues + s->cdlms[ich][ilms].order,
+ s->cdlms[ich][ilms].lms_prevvalues,
+ bps * s->cdlms[ich][ilms].order);
+ memcpy(s->cdlms[ich][ilms].lms_updates + s->cdlms[ich][ilms].order,
+ s->cdlms[ich][ilms].lms_updates,
+ bps * s->cdlms[ich][ilms].order);
+ s->cdlms[ich][ilms].recent = s->cdlms[ich][ilms].order;
+ }
+}
+
/**
*@brief Decode a single subframe (block).
*@param s codec context
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