RE: [Helix-client-dev] CR: [Bug 11177] [U1]:The wma file can be played successfully, but if seek forward, there is no audio sometimes

Qiang

Thanks. Checked into 361/362. I will try to figure out the root reason.

Renjie
________________________________________
From: Qiang Luo
Sent: Wednesday, October 13, 2010 11:09 AM
To: Renjie Huang
Cc: [email protected]; [email protected]; [email protected]
Subject: Re: [Helix-client-dev] CR: [Bug 11177] [U1]:The wma file can be played successfully, but if seek forward, there is no audio sometimes

The workaround is OK for android product branches.

We should find the right fix for 310 and head branches.  Sounds like you
are on the right track with detailed analysis.

Qiang

On 10/7/2010 9:59 AM, Renjie Huang wrote:
> Date: 2010-10-7
> Project: RealPlayer for Android Smartphones
>
> Synopsis: The Windows Media Audio 9 Voice decoder gets false information when seek forward and thus fails decode the bitstream.
>
> Overview: For audio clips in format of Windows Media Audio 9 Voice, when seek forward, Helix entered REBUFFERING mode due to audio underflow; but it does not return back to REBUFDONE and drains all packets causing no sound. The reason: When fake decoder decoding a speech superframe, it checks if there is any trailing silence bits. When seek forward, the result of the check becomes true, which is wrong. Then the decoder continues to check wheather having enough bits to decode the trailing silence bits, it will find that the number of bits is beyond the valid range (psdec->m_nSamplesPerFrame * psdec->m_nFramesPerSuperframe) = 480. In the original code, the decoder simply returns FAILURE, and there is always audio data underflow causing all packets drained immediately. Still unable to figure out why the check of trailing silence bits becomes true when seek forward. In this workaround fix, if the detectes the bit number is beyond the range of psdec->m_nSamplesPerFrame * psdec->m_nFramesPerSuperframe, do not set *pcSampleReady and do not return FAIL neither so that the decoder can continue to decode and feed data to audio device.
>
> Changed files: datatype-restricted/wm/audio/codec/wma9voice/import/wmspv9_dec/audio/wmspeech/v10/stvoicedec/wmsdecstream.c
>
> Platforms and Profiles Affected:
> Platform: hxclient_3_6_1_atlas, hxclient_3_6_2_atlas
> Profile: helix-client-android
>
> Distribution Libraries Affected:
> NA
>
> Distribution library impact and planned action:
> NA
>
> Platforms and Profiles Build Verified:
> Platform: hxclient_3_6_1_atlas
> Profile:  helix-client-android
>
> Platforms and Profiles Functionality verified:
> Platform: hxclient_3_6_1_atlas
> Profile: helix-client-android
> Branch: hxclient_3_6_1_atlas
>
> Copyright assignment: I am a RealNetworks employee or contractor
>
> Index: wmsdecstream.c
> ===================================================================
> RCS file: /cvsroot/wmcode-audio/codec/wma9voice/import/wmspv9_dec/audio/wmspeech/v10/stvoicedec/wmsdecstream.c,v
> retrieving revision 1.1.2.2
> diff -u -w -r1.1.2.2 wmsdecstream.c
> --- wmsdecstream.c  9 Dec 2008 07:37:02 -0000   1.1.2.2
> +++ wmsdecstream.c  7 Oct 2010 01:52:01 -0000
> @@ -170,11 +170,13 @@
>                   *piBitsEnd = iEnd;
>                   return(TraceResult(WMA_E_ONHOLD));
>               } else {
> -                *pcSampleReady = prvExtractBits(pbDataPtr,
> +                U32 uSampleReadyTmp =  prvExtractBits(pbDataPtr,
>                                   (*piBitsEnd)-TRAILING_SILENCE_BITS, TRAILING_SILENCE_BITS);
> +
>                   //assert(*pcSampleReady<= (U32)(psdec->m_nSamplesPerFrame * psdec->m_nFramesPerSuperframe));
> -                if (*pcSampleReady>  (U32)(psdec->m_nSamplesPerFrame * psdec->m_nFramesPerSuperframe)) {
> -                    return(TraceResult(WMA_E_FAIL));
> +                if (uSampleReadyTmp<= (U32)(psdec->m_nSamplesPerFrame * psdec->m_nFramesPerSuperframe))
> +                {
> +                   *pcSampleReady = uSampleReadyTmp;
>                   }
>               }
>           }
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