[Libav-user] Fw: Fw: Getting "No frame: error

krishnaks at iwavesystems.com krishnaks at iwavesystems.com
Mon Apr 23 12:44:55 CEST 2012


Hi,

I just tried with the code in doc/Examples/decoding_encoding.c for video
decoding & I am getting following errors

Invalid level prefix
[h264 @ 0xb86b800] error while decoding MB 5 6
[h264 @ 0xb86b800] concealing 77 DC, 77 AC, 77 MV errors
saving frame   0

Regards,
KP

> Hi Alex.
>
> I thought I may need to add NAL units That why I added 0x00000001.
>
> Please see the  code: Let me know If I am missing..
>
> av_register_all();
> codec = avcodec_find_decoder(CODEC_ID_H264);
> 		codecCtx = avcodec_alloc_context3(codec);
>
> 		codecCtx->width = width;
> 		codecCtx->height = height;
>
> 		codecCtx->extradata = (uint8_t*)av_malloc([frameData length]);
> 		codecCtx->extradata_size = [frameData length];
> 		[privateData getBytes:codecCtx->extradata
> length:codecCtx->extradata_size];
> 		codecCtx->pix_fmt = PIX_FMT_YUV420P;
>
> 		srcFrame = avcodec_alloc_frame();
> 		dstFrame = avcodec_alloc_frame();
>
>         if(codec->capabilities&CODEC_CAP_TRUNCATED)
>             codecCtx->flags|= CODEC_FLAG_TRUNCATED;
>
> 		int res = avcodec_open2(codecCtx, codec,NULL);
> 		if (res < 0)
> 		{
> 			NSLog(@"Failed to initialize decoder");
> 		}
>
>       packet.data = (uint8_t*)[frameData bytes];
> 	packet.size = [frameData length];
>
> 	 int frameFinished = 0;
>
>     int res = avcodec_decode_video2(codecCtx, srcFrame, &frameFinished,
> &packet);
>
>
> Regards,
> KP
>> ----- Original Message -----
>> From: "Alex Cohn" <alexcohn at netvision.net.il>
>> To: "This list is about using libavcodec, libavformat,
>> libavutil,libavdevice
>> and libavfilter." <libav-user at ffmpeg.org>
>> Sent: Monday, April 23, 2012 3:03 AM
>> Subject: Re: [Libav-user] Fw: Getting "No frame: error
>>
>>
>>> On Mon, Apr 23, 2012 at 09:23,  <krishnaks at iwavesystems.com> wrote:
>>>> Hi,
>>>>
>>>> I have prefixed each frame with 0x00000001 &
>>>
>>> Why?
>>>
>>>> I am getting Following error
>>>>
>>>> [h264 @ 0x906e400] non-existing PPS 0 referenced
>>>>
>>>>>>> VLC player able to play the input video. I will check with ffmpeg
>>>>>>> util
>>>
>>> are you decoding a stream or a file? What is the file/stream format
>>> (mpeg4, mkv, mp4)?
>>>
>>>>>>>> I have linked ffmpeg & live555 library to my IOS application.
>>>>>>>> I am receiving the h264 encoded frame and sending the frame to
>>>>>>>> dcoder.
>>>>>>>> But Decoder throws the error:
>>>>>>>>
>>>>>>>> [h264 @ 0x8a4ac00] no frame!
>>>
>>> how do you initialize your decoder?
>>>
>>> BR,
>>> Alex
>>> _______________________________________________
>>> Libav-user mailing list
>>> Libav-user at ffmpeg.org
>>> http://ffmpeg.org/mailman/listinfo/libav-user
>>
>>
>
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