[FFmpeg-devel] [PATCH] avcodec: add PhotoCD decoder

Paul B Mahol onemda at gmail.com
Fri Sep 4 16:29:18 EEST 2020


On 8/30/20, Paul B Mahol <onemda at gmail.com> wrote:
> On 8/30/20, Andreas Rheinhardt <andreas.rheinhardt at gmail.com> wrote:
> [...]
>>> +static int read_hufftable(AVCodecContext *avctx, VLC *vlc)
>>> +{
>>> +    PhotoCDContext *s = avctx->priv_data;
>>> +    GetByteContext *gb = &s->gb;
>>> +    int start = s->streampos;
>>> +    int count, ret;
>>> +
>>> +    bytestream2_seek(gb, start, SEEK_SET);
>>> +
>>> +    count = bytestream2_get_byte(gb) + 1;
>>> +
>>
>> With this information you can check once whether there is enough data
>> left, allowing you to use the unchecked versions of the bytestream2 API.
>
> Fixed locally.
>
>>
>>> +    ff_free_vlc(vlc);
>>> +
>>> +    for (int j = 0; j < count; j++) {
>>> +        const int bit  = bytestream2_get_byte(gb) + 1;
>>> +        const int code = bytestream2_get_be16(gb) >> (16 - bit);
>>
>> You are using bit here before having validated it.
>
> Fixed locally.
>
> [...]
>


Gonna apply with few other small changes.


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