Hi Andrzej,
>>> downmix_buf is allocated to have buffer size FIXED_BUFFER_SIZE / 2, when
>>> we access it as (int16_t *) we shall device index by 2.
>>> ---
>>> android/hal-audio.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/android/hal-audio.c b/android/hal-audio.c
>>> index 7305bb6..96fa5c3 100644
>>> --- a/android/hal-audio.c
>>> +++ b/android/hal-audio.c
>>> @@ -984,7 +984,7 @@ static void downmix_to_mono(struct a2dp_stream_out *out, const uint8_t *buffer,
>>> int16_t *output = (void *) out->downmix_buf;
>>> size_t i;
>>>
>>> - for (i = 0; i < bytes / 2; i++) {
>>> + for (i = 0; i < bytes / (2 * sizeof(int16_t)); i++) {
>>> int16_t l = le16_to_cpu(get_unaligned(&input[i * 2]));
>>> int16_t r = le16_to_cpu(get_unaligned(&input[i * 2 + 1]));
>>
>> I wonder actually what this get_unaligned is doing here? You cast the const void into const int16_t buffer. Is this really needed? Where is our input and output buffer coming from? Aren’t these aligned anyway? Meaning aren’t they allocated?
>
> We have this buffer from AudioFlinger so we don't actually know
> alignment or if this is pointer to beginning of some internal buffer
> (it's most probably both, but I don't think we should assume this).
and audio system that does not give you a guarantee here on the alignment is utterly screwed up. Seriously, that is just bad for performance. Especially bad on ARM CPUs, so I doubt that they have not thought about this.
Regards
Marcel
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