Roon

[volpone75]

(07-27-2017, 06:01 PM)ThierryNK a écrit : ....
Je dis que c'est de l'enfumage, parce que la "vérité" est que suivant la charge des matériels informatiques, on n'écoute pas la même piste, et qu'il est erroné d'affirmer que:

Citation :we also know that both TCP and UDP, when implemented properly, are suitable for high-bandwidth, high-quality media streaming

High bandwidth oui
High quality non

Ils sont passés en TCP le mois dernier,  OK, tant mieux pour les aficionados de Roon.

Encore une fois péremptoire @ThierryNK et pas à bon escient. Cela nous remet dans l'ambiance estivale chaude du début de ce fil. Pas productif et en tous cas pas agréable comme mode d'échange. Sur l'enfumage je me demande parfois ...

Un complément d'info sur l'implémentation de RAAT en version UDP: C'est pas flou et il n'y a pas de loup.

Brian Luczkiewicz Roon Labs CTO a écrit :We would have to be complete and utter fools to design an streaming protocol for music playback that dropped audio each time a single UDP packet was lost.

RAAT has a reliability mechanism that detects dropped UDP packets and re-transmits them. There is a substantial buffer in the endpoint, which allows us to potentially retry many times before it becomes "too late". RAAT is a reliable protocol, just like TCP.

Any networked audio playback system--regardless of whether it is based on TCP, or UDP, has to make a decision about what to do if the data does not "get there" in time. In RAAT's case, this means that an audio packet was dropped, and then 20 or more re-transmit attempts for that packet failed (in other words, the network is totally broken).

Were that to happen, RAAT would replace the missing audio with 0-samples (PCM) or 0x69 samples (DSD).

A whole packet of missing audio would produce an audible click/pop that would be jarring to a layman who's not paying close attention, and it would reflect as a string of hundreds of 0-samples on a capture like the one you posted.

.....

UDP has a checksum mechanism built in to prevent the delivery of corrupt packets (corrupt packets are dropped before they reach our code), so additional checksums on our end are not needed--detecting drops is sufficient.

We do use TCP to report dropouts back to Roon when they occur. Dropouts are tracked and logged. If a concerning quantity is detected, Roon ends playback, displays a message to the user, and moves onto the next track.