From e6e7bfc11e93fe3499c576fa9466cb2e913b5965 Mon Sep 17 00:00:00 2001 From: Kostya Shishkov Date: Sun, 15 Jan 2012 14:23:28 +0100 Subject: wavpack: fix clipping for 32-bit lossy mode Reference decoder clips data before shifting it to final range and also forces 32-bit lossy mode to be actually 24-bit lossy mode in order to be able to perform proper clipping. --- libavcodec/wavpack.c | 27 +++++++++++++++++++-------- 1 file changed, 19 insertions(+), 8 deletions(-) (limited to 'libavcodec/wavpack.c') diff --git a/libavcodec/wavpack.c b/libavcodec/wavpack.c index 6896877fca..1098873d7c 100644 --- a/libavcodec/wavpack.c +++ b/libavcodec/wavpack.c @@ -112,7 +112,8 @@ typedef struct WavpackFrameContext { int extra_bits; int and, or, shift; int post_shift; - int hybrid, hybrid_bitrate, hybrid_maxclip; + int hybrid, hybrid_bitrate; + int hybrid_maxclip, hybrid_minclip; int float_flag; int float_shift; int float_max_exp; @@ -412,12 +413,12 @@ static inline int wv_get_value_integer(WavpackFrameContext *s, uint32_t *crc, } bit = (S & s->and) | s->or; - bit = (((S + bit) << s->shift) - bit) << s->post_shift; + bit = ((S + bit) << s->shift) - bit; if (s->hybrid) - bit = av_clip(bit, -s->hybrid_maxclip - 1, s->hybrid_maxclip); + bit = av_clip(bit, s->hybrid_minclip, s->hybrid_maxclip); - return bit; + return bit << s->post_shift; } static float wv_get_value_float(WavpackFrameContext *s, uint32_t *crc, int S) @@ -763,7 +764,7 @@ static int wavpack_decode_block(AVCodecContext *avctx, int block_no, const uint8_t *orig_buf = buf; const uint8_t *buf_end = buf + buf_size; int i, j, id, size, ssize, weights, t; - int bpp, chan, chmask; + int bpp, chan, chmask, orig_bpp; if (buf_size == 0) { *got_frame_ptr = 0; @@ -799,15 +800,16 @@ static int wavpack_decode_block(AVCodecContext *avctx, int block_no, s->frame_flags = AV_RL32(buf); buf += 4; bpp = av_get_bytes_per_sample(avctx->sample_fmt); samples = (uint8_t*)samples + bpp * wc->ch_offset; + orig_bpp = ((s->frame_flags & 0x03) + 1) << 3; s->stereo = !(s->frame_flags & WV_MONO); s->stereo_in = (s->frame_flags & WV_FALSE_STEREO) ? 0 : s->stereo; s->joint = s->frame_flags & WV_JOINT_STEREO; s->hybrid = s->frame_flags & WV_HYBRID_MODE; s->hybrid_bitrate = s->frame_flags & WV_HYBRID_BITRATE; - s->hybrid_maxclip = (1LL << ((((s->frame_flags & 0x03) + 1) << 3) - 1)) - 1; - s->post_shift = 8 * (bpp - 1 - (s->frame_flags & 0x03)) + - ((s->frame_flags >> 13) & 0x1f); + s->post_shift = bpp * 8 - orig_bpp + ((s->frame_flags >> 13) & 0x1f); + s->hybrid_maxclip = (( 1LL << (orig_bpp - 1)) - 1) >> s->post_shift; + s->hybrid_minclip = ((-1LL << (orig_bpp - 1))) >> s->post_shift; s->CRC = AV_RL32(buf); buf += 4; if (wc->mkv_mode) buf += 4; //skip block size; @@ -968,6 +970,15 @@ static int wavpack_decode_block(AVCodecContext *avctx, int block_no, s->and = 1; s->shift = buf[3]; } + /* original WavPack decoder forces 32-bit lossy sound to be treated + * as 24-bit one in order to have proper clipping + */ + if (s->hybrid && bpp == 4 && s->post_shift < 8 && s->shift > 8) { + s->post_shift += 8; + s->shift -= 8; + s->hybrid_maxclip >>= 8; + s->hybrid_minclip >>= 8; + } buf += 4; break; case WP_ID_FLOATINFO: -- cgit v1.2.3