On 11/26/19, James Almer <jamr...@gmail.com> wrote:
> On 11/25/2019 6:09 PM, Paul B Mahol wrote:
>> Signed-off-by: Paul B Mahol <one...@gmail.com>
>> ---
>> libavcodec/Makefile | 1 +
>> libavcodec/allcodecs.c | 1 +
>> libavcodec/avcodec.h | 1 +
>> libavcodec/codec_desc.c | 7 ++
>> libavcodec/midivid.c | 272 ++++++++++++++++++++++++++++++++++++++++
>> libavformat/riff.c | 1 +
>> 6 files changed, 283 insertions(+)
>> create mode 100644 libavcodec/midivid.c
>
> [...]
>
>> diff --git a/libavcodec/midivid.c b/libavcodec/midivid.c
>> new file mode 100644
>> index 0000000000..36ed4b83bd
>> --- /dev/null
>> +++ b/libavcodec/midivid.c
>> @@ -0,0 +1,272 @@
>> +/*
>> + * MidiVid decoder
>> + * Copyright (c) 2019 Paul B Mahol
>> + *
>> + * 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 <stdio.h>
>> +#include <stdlib.h>
>> +#include <string.h>
>> +
>> +#include "libavutil/imgutils.h"
>> +#include "libavutil/internal.h"
>> +#include "libavutil/intreadwrite.h"
>> +#include "libavutil/mem.h"
>> +
>> +#define BITSTREAM_READER_LE
>> +#include "avcodec.h"
>> +#include "get_bits.h"
>> +#include "bytestream.h"
>> +#include "internal.h"
>> +
>> +typedef struct MidiVidContext {
>> + GetByteContext gb;
>> +
>> + uint8_t *uncompressed;
>> + int uncompressed_size;
>
> Should be unsigned int, seeing it's used as argument for
> av_fast_padded_malloc().
Ok.
>
>> + uint8_t *skip;
>> +
>> + AVFrame *frame;
>> +} MidiVidContext;
>> +
>> +static int decode_mvdv(MidiVidContext *s, AVCodecContext *avctx, AVFrame
>> *frame)
>> +{
>> + GetByteContext *gb = &s->gb;
>> + GetBitContext mask;
>> + GetByteContext idx9;
>> + uint16_t nb_vectors, intra_flag;
>> + const uint8_t *vec;
>> + const uint8_t *mask_start;
>> + uint8_t *skip;
>> + int mask_size;
>> + int idx9bits = 0;
>> + int idx9val = 0;
>> + int num_blocks;
>> +
>> + nb_vectors = bytestream2_get_le16(gb);
>> + intra_flag = bytestream2_get_le16(gb);
>> + if (intra_flag) {
>> + num_blocks = (avctx->width / 2) * (avctx->height / 2);
>> + } else {
>> + int skip_linesize;
>> +
>> + num_blocks = bytestream2_get_le32(gb);
>> + skip_linesize = avctx->width >> 1;
>> + mask_start = gb->buffer_start + bytestream2_tell(gb);
>> + mask_size = (avctx->width >> 5) * (avctx->height >> 2);
>> + init_get_bits8(&mask, mask_start, mask_size);
>> + bytestream2_skip(gb, mask_size);
>> + skip = s->skip;
>> +
>> + for (int y = 0; y < avctx->height >> 2; y++) {
>> + for (int x = 0; x < avctx->width >> 2; x++) {
>> + int flag = !get_bits1(&mask);
>> +
>> + skip[(y*2) *skip_linesize + x*2 ] = flag;
>> + skip[(y*2) *skip_linesize + x*2+1] = flag;
>> + skip[(y*2+1)*skip_linesize + x*2 ] = flag;
>> + skip[(y*2+1)*skip_linesize + x*2+1] = flag;
>> + }
>> + }
>> + }
>> +
>> + vec = gb->buffer_start + bytestream2_tell(gb);
>
> Isn't this the same as doing vec = g->buffer?
No point in changing now.
>
>> + if (bytestream2_get_bytes_left(gb) < nb_vectors * 12)
>> + return AVERROR_INVALIDDATA;
>> + bytestream2_skip(gb, nb_vectors * 12);
>> + if (nb_vectors > 256) {
>> + if (bytestream2_get_bytes_left(gb) < (num_blocks + 7) / 8)
>> + return AVERROR_INVALIDDATA;
>> + bytestream2_init(&idx9, gb->buffer_start + bytestream2_tell(gb),
>> (num_blocks + 7) / 8);
>
> Ditto.
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