From patchwork Mon Nov 2 09:38:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zane van Iperen X-Patchwork-Id: 23326 Return-Path: X-Original-To: patchwork@ffaux-bg.ffmpeg.org Delivered-To: patchwork@ffaux-bg.ffmpeg.org Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by ffaux.localdomain (Postfix) with ESMTP id B3348449970 for ; Mon, 2 Nov 2020 11:38:23 +0200 (EET) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 9B5A168B5F7; Mon, 2 Nov 2020 11:38:23 +0200 (EET) X-Original-To: ffmpeg-devel@ffmpeg.org Delivered-To: ffmpeg-devel@ffmpeg.org Received: from mail-40133.protonmail.ch (mail-40133.protonmail.ch [185.70.40.133]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 17E7668B5F4 for ; Mon, 2 Nov 2020 11:38:17 +0200 (EET) Date: Mon, 02 Nov 2020 09:38:12 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zanevaniperen.com; s=protonmail2; t=1604309896; bh=UIscjNGxtI9+AWe6QkYnTJ6eGvXAHW2fPZ+esyD1UWk=; h=Date:To:From:Cc:Reply-To:Subject:In-Reply-To:References:From; b=2tLqbfLpBPezevlBnrKkrOHfnXx2X3Ev3QnZAECHAHK1YK9QN38DMHum0SUqzJVU+ mid647NS96ooN12eD3w/Z3AaP0bfGro0v5PjvNC0Y77wY0cSxOi9Zx9iZEH+ztrN2g Isvcs+vJGR4N3MyBabheLZrUx0Kbu+9Urxj/7CbikLzxg5yzy5i0ADpj9o7x5dX8qk OTBMTxZuLNhiTnbbq2ciDwdNykydmAJCoAP1jXwx425lF4PHqE9TAGKbNePeJTghoF jtbSnjkGMc3EHrrZGkxH0mWaJeYGGl9QrMgMjt1kPLb4bySWcsKrARAJQbGT8qIN57 GSShvN86l4FRA== To: ffmpeg-devel@ffmpeg.org From: Zane van Iperen Message-ID: <20201102093738.12430-4-zane@zanevaniperen.com> In-Reply-To: <20201102093738.12430-1-zane@zanevaniperen.com> References: <20201102093738.12430-1-zane@zanevaniperen.com> MIME-Version: 1.0 X-Spam-Status: No, score=-1.2 required=10.0 tests=ALL_TRUSTED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF shortcircuit=no autolearn=disabled version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on mailout.protonmail.ch Subject: [FFmpeg-devel] [PATCH 3/5] avcodec/adpcm_ima_amv: document header format X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches Cc: Zane van Iperen Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Signed-off-by: Zane van Iperen --- libavcodec/adpcm.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/libavcodec/adpcm.c b/libavcodec/adpcm.c index d0807cbd98..7f2c958d16 100644 --- a/libavcodec/adpcm.c +++ b/libavcodec/adpcm.c @@ -1698,6 +1698,16 @@ static int adpcm_decode_frame(AVCodecContext *avctx, void *data, case AV_CODEC_ID_ADPCM_IMA_AMV: av_assert0(avctx->channels == 1); + /* + * Header format: + * int16_t predictor; + * uint8_t step_index; + * uint8_t reserved; + * uint32_t frame_size; + * + * Some implementations have step_index as 16-bits, but others + * only use the lower 8 and store garbage in the upper 8. + */ c->status[0].predictor = sign_extend(bytestream2_get_le16u(&gb), 16); c->status[0].step_index = bytestream2_get_byteu(&gb); bytestream2_skipu(&gb, 5);