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| author | Andreas Rheinhardt <andreas.rheinhardt@gmail.com> | 2020-10-29 11:12:32 +0100 |
|---|---|---|
| committer | Andreas Rheinhardt <andreas.rheinhardt@gmail.com> | 2020-12-08 17:51:45 +0100 |
| commit | 949367b0ec660d2496a62f7acc359bac651bdc02 (patch) | |
| tree | ff860c8dda7d7a794c9a5713e6e24d5f3ac73a0b | |
| parent | b9dc000679c55ff2c013bdea17b2235228b1ac3f (diff) | |
| download | ffmpeg-949367b0ec660d2496a62f7acc359bac651bdc02.tar.gz | |
avcodec/motionpixels: Simplify creating VLC tables
By using ff_init_vlc_from_lengths(), we do not have to keep track of the
codes themselves, but can offload this to ff_init_vlc_from_lengths().
Furthermore, the old code presumed sizeof(int) == 4; this is no longer
so.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
| -rw-r--r-- | libavcodec/motionpixels.c | 19 |
1 files changed, 9 insertions, 10 deletions
diff --git a/libavcodec/motionpixels.c b/libavcodec/motionpixels.c index 909299b5ef..b08a2f624b 100644 --- a/libavcodec/motionpixels.c +++ b/libavcodec/motionpixels.c @@ -33,7 +33,6 @@ #include "motionpixels_tablegen.h" typedef struct HuffCode { - int code; uint8_t size; uint8_t delta; } HuffCode; @@ -129,7 +128,7 @@ static void mp_read_changes_map(MotionPixelsContext *mp, GetBitContext *gb, int } } -static int mp_get_code(MotionPixelsContext *mp, GetBitContext *gb, int size, int code) +static int mp_get_code(MotionPixelsContext *mp, GetBitContext *gb, int size) { while (get_bits1(gb)) { ++size; @@ -137,8 +136,7 @@ static int mp_get_code(MotionPixelsContext *mp, GetBitContext *gb, int size, int av_log(mp->avctx, AV_LOG_ERROR, "invalid code size %d/%d\n", size, mp->max_codes_bits); return AVERROR_INVALIDDATA; } - code <<= 1; - if (mp_get_code(mp, gb, size, code + 1) < 0) + if (mp_get_code(mp, gb, size) < 0) return AVERROR_INVALIDDATA; } if (mp->current_codes_count >= mp->codes_count) { @@ -146,7 +144,6 @@ static int mp_get_code(MotionPixelsContext *mp, GetBitContext *gb, int size, int return AVERROR_INVALIDDATA; } - mp->codes[mp->current_codes_count ].code = code; mp->codes[mp->current_codes_count++].size = size; return 0; } @@ -163,7 +160,7 @@ static int mp_read_codes_table(MotionPixelsContext *mp, GetBitContext *gb) for (i = 0; i < mp->codes_count; ++i) mp->codes[i].delta = get_bits(gb, 4); mp->current_codes_count = 0; - if ((ret = mp_get_code(mp, gb, 0, 0)) < 0) + if ((ret = mp_get_code(mp, gb, 0)) < 0) return ret; if (mp->current_codes_count < mp->codes_count) { av_log(mp->avctx, AV_LOG_ERROR, "too few codes\n"); @@ -329,10 +326,12 @@ static int mp_decode_frame(AVCodecContext *avctx, goto end; if (mp->codes_count > 1) { - ret = ff_init_vlc_sparse(&mp->vlc, mp->max_codes_bits, mp->codes_count, - &mp->codes[0].size, sizeof(HuffCode), 1, - &mp->codes[0].code, sizeof(HuffCode), 4, - &mp->codes[0].delta, sizeof(HuffCode), 1, 0); + /* The entries of the mp->codes array are sorted from right to left + * in the Huffman tree, hence -(int)sizeof(HuffCode). */ + ret = ff_init_vlc_from_lengths(&mp->vlc, mp->max_codes_bits, mp->codes_count, + &mp->codes[mp->codes_count - 1].size, -(int)sizeof(HuffCode), + &mp->codes[mp->codes_count - 1].delta, -(int)sizeof(HuffCode), 1, + 0, 0, avctx); if (ret < 0) goto end; } |