[Libav-user] FFMPEG to decode I frames

[Mercier, T.J.]

I had the same problem as you, but this worked for me: "I tried sending a NULL packet and using avocdec_flush_buffers() to flush out the decoded frame"

Even though it was functionally correct, that approach was too slow. If I remember correctly that was due to (re)initialization time for the decoder.


However, I ended up moving all the decode to NVDEC directly anyway.


________________________________
From: Libav-user <libav-user-bounces at ffmpeg.org> on behalf of rohit khali <khali.rohit at gmail.com>
Sent: Friday, November 6, 2020 12:43 AM
To: This list is about using libavcodec, libavformat, libavutil, libavdevice and libavfilter.
Subject: [EXTERNAL] [Libav-user] FFMPEG to decode I frames


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Hi,

My application parses only I frames from H264 bit stream and hands it over to FFMPEG decoder.
Expectation was that FFMPEG decoder  immediately output decoded frames since input is I frame. However, FFMPEG can't do this especially for cases where I frame is not an IDR.

I tried sending a NULL packet and using avocdec_flush_buffers() to flush out the decoded frame but this logic doesn't seem to work for all cases, maybe again depending on DPB size or POC.
I was wondering if anyone else has used FFMPEG for such a use case earlier and what else I can use to immediately receive the I frames.

Thanks,
Rohit Khali
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