Hi all, Is there a way to get hold of low level information, i.e. partial decodings, of an mp4 file? Since this is all I need for my analysis, I hope it would be more efficient than decoding the entire video:
1. key frames (skipping motion compensation frames) as decoded images 2. p-frame motion vectors... I know h264 gets a bit more complex with full inter-frame but just forward motion estimation is fine. 3. the fourier space from AAC (or anything that would resemble the DTFT... I realise this is a bit more ill-defined, it's not as important) It looks like libavcodec is the closest thing to what I'm looking for: https://www.ffmpeg.org/doxygen/3.2/group__lavc__encdec.html https://www.ffmpeg.org/doxygen/3.2/group__lavc__decoding.html I'm not a C developer, so I'm not very proficient at understanding the documentation. (I'm looking to do something on the JVM and I'm experienced with JNI / JNA / etc, but I think I can translate the C once I find exactly what I need to do.) Would I be right in saying that I need to call avcodec_send_packet() ? Then I'm lost. How would I be able to detect what kind of packet this is, e.g. to determine if it is key or p-frame, and then be able to uncompress it into a JPEG or motion vectors (dropping the residue). Best regards, Sam _______________________________________________ Libav-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/libav-user
