JB,

 
>>  > I made a few tests with the Decklink producer, using an Intensity Pro
>>  > card. I can correctly preview the video:
>>  > 
>>  > melt -profile atsc_1080i_50 decklink:0
>>  > 
>>  > However, when I try to encode the stream using an avformat consumer, 
> the
>>  > process quickly eats all my memory (goes up to more than 1 Giga in 20
>>  > seconds) and then freezes my system.
>>  > 
>>  > I used the following command to encode:
>>  > 
>>  > melt -profile atsc_1080i_50 decklink:0 -consumer avformat:test.mpg
>>  > vcodec=mpeg2video minrate=0 b=6000k acodec=mp2 ab=128k ar=48000
>>  > 
>>  > I tried a few other encoding params without more success. Any ideas? 
> Is
>>  > it because encoding is too slow and MLT caches more and more frames? 
> Did
>>  > anybody succeed in capturing from the decklink producer to a file?
>> 
>>  What is the CPU utilization when running melt? If it is 100%, then you
>>  don't have enough resources to encode HD MPEG2 video in real time. Keep 
> in
>>  mind that the encoding process may not be easily distributed across cores.
>>  So, if the CPU core that is doing the encoding is at 100%, it may not
>>  matter if other cores are less than 100%.
> 
> Hi Brian.
> 
> Yes, the CPU usage is quite high, between 70 and 90% for the 2 cores (I have 
> a 
> 4 years old dual core pc). If you have suggestions about using another codec 
> or FFmpeg parameters that would not require that much CPU, it is welcome.

For real time MPEG2 HD encoding, I would have expected that you would need 
better performance than a 4 year old dual core processor.

If I were you, I would be nervous about the 90% utilization and I would test 
thoroughly to make sure no frames are being dropped.

There are some tips here that you might find helpful:
http://smorgasbork.com/component/content/article/35-linux/98-high-bitrate-real-time-mpeg-2-encoding-with-ffmpeg

~Brian


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