[FFmpeg-devel] v4l2: bug #1570 and possible solution

[Giorgio Vazzana]

2013/2/12 Giorgio Vazzana <mywing81 at gmail.com>:
> 2013/2/12 Michael Niedermayer <michaelni at gmx.at>:
>> On Tue, Feb 12, 2013 at 12:40:21PM +0100, Giorgio Vazzana wrote:
>>> 2013/2/12 Michael Niedermayer <michaelni at gmx.at>:
>>> +static void mmap_release_buffer(AVPacket *pkt)
>>> +{
>>> +    struct buff_data *buf_descriptor = pkt->priv;
>>> +
>>> +    if (pkt->data == NULL)
>>> +        return;
>>> +
>>> +    if (buf_descriptor->buffer_copied) {
>>> +        av_free(pkt->data);
>>> +    } else {
>>> +        if (!enqueue_buffer(buf_descriptor->fd, buf_descriptor->index))
>>
>>> +            (*buf_descriptor->buffers_dequeued)--;
>>
>> the deallocation of packets could happen from different thread(s)
>> so i think this needs either a mutex, an atomic decrement or some
>> lockless algorithm to achive the same
>
> Ok, I've tried to implement the solution using the mutex. Please comment.

Sorry, this was a previous version of the patch, the latest one is attached.

> We can use this approach, or the easiest (and slightly slower?)
> solution would be copying every frame/buffer to the memory allocated
> for the corresponding packet.
>
> Giorgio Vazzana
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