From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mta.bitpro.no ([92.42.64.202]:59713 "EHLO mta.bitpro.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966916Ab3E3IOY (ORCPT ); Thu, 30 May 2013 04:14:24 -0400 Message-ID: <51A70713.6030802@bitfrost.no> Date: Thu, 30 May 2013 10:00:19 +0200 From: Hans Petter Selasky MIME-Version: 1.0 To: linux-media@vger.kernel.org, Juergen Lock Subject: TT-USB2.0 and high bitrate packet loss (DVB-C/T) Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Hi there, I need to get in concat with someone that can handle, test and review a patch for TT-USB2.0. I've found that for certain high-bitrate streams, the TT-USB2.0 sends more ISOCHRONOUS MPEG data than is specified in the wMaxPacketSize fields. I have a USB analyzer capture which shows this clearly. This of course won't be received at the USB host and packet drops appear inside the stream. The solution is to use another alternate setting. The technotrend chip has many of these. I've now tested using alternate setting 7 instead of 3. Alternate setting 7 allows transferring a maximum of 3 * 1024 bytes. Alternate setting 3 allows transferring a maximum of 1 * 940 bytes. --HPS