From 0fb2182d469d09623cf2ff0e4b786981f2fbafbe Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Sat, 21 Mar 2009 01:54:31 +0000
Subject: [PATCH] add a function to calculate a more accurate estimate for
maximum FLAC frame size and use the function in the FLAC decoder and FLAC
encoder
Originally committed as revision 18092 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
libavcodec/Makefile | 16 ++++++++--------
libavcodec/flac.c | 43 +++++++++++++++++++++++++++++++++++++++++++
libavcodec/flac.h | 8 ++++++++
libavcodec/flacdec.c | 3 ++-
libavcodec/flacenc.c | 7 ++-----
5 files changed, 63 insertions(+), 14 deletions(-)
create mode 100644 libavcodec/flac.c
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 7683402f560..4843e0933ac 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -83,8 +83,8 @@ OBJS-$(CONFIG_FFV1_DECODER) += ffv1.o rangecoder.o
OBJS-$(CONFIG_FFV1_ENCODER) += ffv1.o rangecoder.o
OBJS-$(CONFIG_FFVHUFF_DECODER) += huffyuv.o
OBJS-$(CONFIG_FFVHUFF_ENCODER) += huffyuv.o
-OBJS-$(CONFIG_FLAC_DECODER) += flacdec.o flacdata.o
-OBJS-$(CONFIG_FLAC_ENCODER) += flacenc.o flacdata.o lpc.o
+OBJS-$(CONFIG_FLAC_DECODER) += flacdec.o flacdata.o flac.o
+OBJS-$(CONFIG_FLAC_ENCODER) += flacenc.o flacdata.o flac.o lpc.o
OBJS-$(CONFIG_FLASHSV_DECODER) += flashsv.o
OBJS-$(CONFIG_FLASHSV_ENCODER) += flashsvenc.o
OBJS-$(CONFIG_FLIC_DECODER) += flicvideo.o
@@ -346,17 +346,17 @@ OBJS-$(CONFIG_ADPCM_YAMAHA_ENCODER) += adpcm.o
# libavformat dependencies
OBJS-$(CONFIG_EAC3_DEMUXER) += ac3_parser.o ac3tab.o aac_ac3_parser.o
-OBJS-$(CONFIG_FLAC_DEMUXER) += flacdec.o flacdata.o
-OBJS-$(CONFIG_FLAC_MUXER) += flacdec.o flacdata.o
+OBJS-$(CONFIG_FLAC_DEMUXER) += flacdec.o flacdata.o flac.o
+OBJS-$(CONFIG_FLAC_MUXER) += flacdec.o flacdata.o flac.o
OBJS-$(CONFIG_GXF_DEMUXER) += mpeg12data.o
-OBJS-$(CONFIG_MATROSKA_AUDIO_MUXER) += xiph.o mpeg4audio.o flacdec.o flacdata.o
+OBJS-$(CONFIG_MATROSKA_AUDIO_MUXER) += xiph.o mpeg4audio.o flacdec.o flacdata.o flac.o
OBJS-$(CONFIG_MATROSKA_DEMUXER) += mpeg4audio.o
-OBJS-$(CONFIG_MATROSKA_MUXER) += xiph.o mpeg4audio.o flacdec.o flacdata.o
+OBJS-$(CONFIG_MATROSKA_MUXER) += xiph.o mpeg4audio.o flacdec.o flacdata.o flac.o
OBJS-$(CONFIG_MOV_DEMUXER) += mpeg4audio.o mpegaudiodata.o
OBJS-$(CONFIG_MPEGTS_MUXER) += mpegvideo.o
OBJS-$(CONFIG_NUT_MUXER) += mpegaudiodata.o
-OBJS-$(CONFIG_OGG_DEMUXER) += flacdec.o flacdata.o
-OBJS-$(CONFIG_OGG_MUXER) += xiph.o flacdec.o flacdata.o
+OBJS-$(CONFIG_OGG_DEMUXER) += flacdec.o flacdata.o flac.o
+OBJS-$(CONFIG_OGG_MUXER) += xiph.o flacdec.o flacdata.o flac.o
OBJS-$(CONFIG_RTP_MUXER) += mpegvideo.o
# external codec libraries
diff --git a/libavcodec/flac.c b/libavcodec/flac.c
new file mode 100644
index 00000000000..a649e08732c
--- /dev/null
+++ b/libavcodec/flac.c
@@ -0,0 +1,43 @@
+/*
+ * FLAC common code
+ * Copyright (c) 2009 Justin Ruggles
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "flac.h"
+
+int ff_flac_get_max_frame_size(int blocksize, int ch, int bps)
+{
+ /* Technically, there is no limit to FLAC frame size, but an encoder
+ should not write a frame that is larger than if verbatim encoding mode
+ were to be used. */
+
+ int count;
+
+ count = 16; /* frame header */
+ count += ch * ((7+bps+7)/8); /* subframe headers */
+ if (ch == 2) {
+ /* for stereo, need to account for using decorrelation */
+ count += (( 2*bps+1) * blocksize + 7) / 8;
+ } else {
+ count += ( ch*bps * blocksize + 7) / 8;
+ }
+ count += 2; /* frame footer */
+
+ return count;
+}
diff --git a/libavcodec/flac.h b/libavcodec/flac.h
index 1e44a3b3941..2728905b79a 100644
--- a/libavcodec/flac.h
+++ b/libavcodec/flac.h
@@ -103,4 +103,12 @@ int ff_flac_is_extradata_valid(AVCodecContext *avctx,
void ff_flac_parse_block_header(const uint8_t *block_header,
int *last, int *type, int *size);
+/**
+ * Calculate an estimate for the maximum frame size based on verbatim mode.
+ * @param blocksize block size, in samples
+ * @param ch number of channels
+ * @param bps bits-per-sample
+ */
+int ff_flac_get_max_frame_size(int blocksize, int ch, int bps);
+
#endif /* AVCODEC_FLAC_H */
diff --git a/libavcodec/flacdec.c b/libavcodec/flacdec.c
index ec1ace4aeeb..8dbe8c91b47 100644
--- a/libavcodec/flacdec.c
+++ b/libavcodec/flacdec.c
@@ -147,7 +147,8 @@ static void allocate_buffers(FLACContext *s)
assert(s->max_blocksize);
if (s->max_framesize == 0 && s->max_blocksize) {
- s->max_framesize = 23 + (s->channels * s->bps * s->max_blocksize + 7) / 8;
+ s->max_framesize = ff_flac_get_max_frame_size(s->max_blocksize,
+ s->channels, s->bps);
}
for (i = 0; i < s->channels; i++) {
diff --git a/libavcodec/flacenc.c b/libavcodec/flacenc.c
index f51a4ee58ba..b517cfa7206 100644
--- a/libavcodec/flacenc.c
+++ b/libavcodec/flacenc.c
@@ -345,11 +345,8 @@ static av_cold int flac_encode_init(AVCodecContext *avctx)
s->options.lpc_coeff_precision);
/* set maximum encoded frame size in verbatim mode */
- if(s->channels == 2) {
- s->max_framesize = 14 + ((s->avctx->frame_size * 33 + 7) >> 3);
- } else {
- s->max_framesize = 14 + (s->avctx->frame_size * s->channels * 2);
- }
+ s->max_framesize = ff_flac_get_max_frame_size(s->avctx->frame_size,
+ s->channels, 16);
/* initialize MD5 context */
s->md5ctx = av_malloc(av_md5_size);
--
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