anyone who can explain more on the difference between segment.abs_rate and segment.abs_applied_rate

[bcxa sz]

On Wed, Oct 19, 2011 at 1:17 PM, Wim Taymans <wim.taymans at gmail.com> wrote:
> On 10/19/2011 05:16 AM, bcxa sz wrote:
>>
>> And I also found the explanation from gst_event_new_new_segment_full():
>> =====================================================
>> * The @applied_rate value provides information about any rate adjustment
>> that
>> * has already been made to the timestamps and content on the buffers of
>> the
>>  * stream. (@rate * @applied_rate) should always equal the rate that has
>> been
>>  * requested for playback. For example, if an element has an input segment
>>  * with intended playback @rate of 2.0 and applied_rate of 1.0, it can
>> adjust
>>  * incoming timestamps and buffer content by half and output a newsegment
>> event
>>  * with @rate of 1.0 and @applied_rate of 2.0
>>
>> ---------------------------------------------------------------------------------------------
>>
>> Can someone explain how and why the rate and applied_rate is changed
>> in above use case?
>
> The easiest way to understand this is to take a piece of paper and write
> down some timestamps and newsegment event values and then calculate the
> stream time and running time of the timestamps.
>
Ok, I will do it. The time caculation and relationship really confused me a lot.

> The rate scales the running time so that playback is slower/faster.
>
> The applied rate scales the stream time so that reported playback time is
> slower/faster.
>
> Wim
>
>>
>> On Wed, Oct 19, 2011 at 10:14 AM, bcxa sz<bcxa.sz at gmail.com>  wrote:
>>>
>>> Hi Developers,
>>>
>>> I am reading the design document on the sync and notice formulas to
>>> calculate the running time and the stream time:
>>>
>>> B.running_time = (B.time_stamp - NS.start) / NS.abs_rate + NS.accum
>>>
>>> stream_time =  (B.time_stamp - NS.start) / NS.abs_applied_rate + NS.accum
>>>
>>> Anyone can explain to me why the running_time use abs_rate but
>>> stream_time use abs_applied_rate?
>>>
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