[FFmpeg-devel] [FFmpeg-cvslog] avcodec: add Ulead DV audio decoder

[Paul B Mahol]

On 1/26/16, Andreas Cadhalpun <andreas.cadhalpun at googlemail.com> wrote:
> On 26.01.2016 23:17, Paul B Mahol wrote:
>> ffmpeg | branch: master | Paul B Mahol <onemda at gmail.com> | Mon Jan 25
>> 21:54:17 2016 +0100| [e9e623369d7ba330ab8157157e956cb71d8058b5] |
>> committer: Paul B Mahol
>>
>> avcodec: add Ulead DV audio decoder
>>
>> Fixes #1564.
>>
>> Signed-off-by: Paul B Mahol <onemda at gmail.com>
>
> Leaving a little bit more time for review would have been nice.
>
>> diff --git a/libavcodec/dvaudiodec.c b/libavcodec/dvaudiodec.c
>> new file mode 100644
>> index 0000000..84db509
>> --- /dev/null
>> +++ b/libavcodec/dvaudiodec.c
>> @@ -0,0 +1,144 @@
> [...]
>> +static int decode_frame(AVCodecContext *avctx, void *data,
>> +                        int *got_frame_ptr, AVPacket *pkt)
>> +{
>> +    DVAudioContext *s = avctx->priv_data;
>> +    AVFrame *frame = data;
>> +    const uint8_t *src = pkt->data;
>> +    int16_t *dst;
>> +    int ret, i;
>> +
>> +    if (pkt->size != s->block_size)
>> +        return AVERROR_INVALIDDATA;
>> +
>> +    frame->nb_samples = dv_get_audio_sample_count(pkt->data + 244,
>> s->is_pal);
>> +    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
>> +        return ret;
>> +    dst = (int16_t *)frame->data[0];
>> +
>> +    for (i = 0; i < frame->nb_samples; i++) {
>
> Maybe this should be 'i < frame->nb_samples / 2'?

Nope.

>
>> +       const uint8_t *v = &src[s->shuffle[i]];
>> +
>> +       if (s->is_12bit) {
>> +           *dst++ = dv_audio_12to16((v[0] << 4) | ((v[2] >> 4) & 0x0f));
>> +           *dst++ = dv_audio_12to16((v[1] << 4) | ((v[2] >> 0) & 0x0f));
>> +       } else {
>> +           *dst++ = AV_RB16(&v[0]);
>
> Because otherwise this can cause out of bounds writes.

Audio is always stereo. Valgrind shows nothing.