Alan Chen via ffmpeg-user wrote: > ffprobe -print_format json -show_packets -show_streams -show_entries > packet=pts,duration,size,codec_type,pos test.mp4 > test.mp4.info
You need to provide more information. What are the contents of test.mp4? What codecs? > I extract the raw data of the packet from the test.mp4 file, take the above > packet as a example, I extract the data at offset = 175 and size = 6419, > then save the packet into a new file, video_sample0.dat. > > I write an app to write all the packets into different audio and video > files, i.e., audio_sample0.dat, audio_sample1.dat, ..., video_sample0.dat, > video_sample1.dat... > > Then I use ffprobe with -show_data option to show the raw data of each > packet, then compare the output with my packet files and confirm they are > identical. > > After that, I remove some useless packets. Then try to recreate a new MP4 > file with the remaining packets. As Ferdi Scholten explained, that won't work. Apart from that, I suspect that you are confusing things. MP4 is a container format, it's *much* more than just a sequence of video packets. It is defined in MPEG-4 part 14 (also known as ISO/IEC 14496-14). > I take one packet file as a test: > > ffmpeg -f m4v -i video_sample0.dat -c copy output.mp4 Are you sure that your file is actually a valid "m4v" stream? I suspect it is not. The error messages that you get from FFmpeg confirm this. In this context, m4v means a video stream according to MPEG-4 part 2 (ISO/IEC 14496-2), including DivX / Xvid. It does *NOT* include H.264 (AVC) or h.265 (HEVC), for example. (Do not confuse it with Apple's MPEG-4 DRM video container format that happens to use the .m4v file name extension, unfortunately, but is unrelated to MPEG-4 part 2.) > So, how to reassemble the raw packet data back to a new MP4 file? That's not possible in general, because your raw packets do not contain sufficient information to create an MP4 file. I suggest that you explain why you are actually doing all of that. What is the purpose, what do you want to achieve actually, on a higher level? There's probable a *much* easier way than trying to dissect the video on the packet level. Best regards -- Oliver _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
