Quote:
Originally Posted by Schmendrick
@Mboufleur: You can demux all the streams with TSRemux. The "MPEGaudio"-files you have to rename *.aac. Winamp is able to play these files and also to convert them to Wav-files. Thus you could e.g. reencode them either to real MPEG-audio or to AC3 and then remux these audiofiles back with TSMuxer.
In the meantime I have downloaded one full sample video. Using TSRemux I demuxed the video- and the audio-stream as avc- and aac-file resepctively. The aac-file I converted into a stereo-wav-file using Winamp with its file-output-plugin. Then I encoded this wav-file with Belight using the AC3enc-encoder into a stereo AC3-256kbit-file. Opening the original "mpg"-ts-file with a hex editor I searched for the first PTS-value of the video stream which can be found if you search for the first occurence of the video flag string "00 00 01 E0" and then the five bytes of the PTS value which is located with a 5 bytes offset after the video flag. In the first sample it is "31 00 CD 33 9D". Then you have to search for the first PTS-value of the audio stream which can be found if you search for the first occurence of the MPEG-audio flag string "00 00 01 C0" and then the five byted of the PTS value which is located with a 5 bytes offset after the MPEG-audio flag. Here it is "21 00 C7 F1 91". As these values are different you have to calculate the time offset so how many seconds the audio is playing too early in this case as the audio-PTS is smaler than the video-PTS, as the least significant bit of the first byte of the PTS values can be ignored so that the "31"-value is equal to the "21"-value of the different PTS-values. As the calculation of the PTS values which is documented in the MPEG ISO standards is quite complicated I have written a simple VideoPTS-Calculator programme:
http://www.alice-dsl.net/schmendrick/VideoPTSCalc.exe
which uses .NET-2.0. You can enter the video PTS-value as the ASCII-string of the hex values of the first five bytes "21 00 CD 33 9D" in the left input box, then guess the time offset value (shift(sec)) in seconds e.g. "-0.82211" which is -822.11 milliseconds, then click on "compute" and obtain the audio PTS value in the right box "new VideoPTS". If you experiment a little with the "shift(sec)"-value you are able to find the exact offset value.
Then using TSMuxer you can remux the avc-video file with your new AC3-audio file using the time offset value in this case -822 milliseconds to obtain a perfectly synchronous ts-file which can be properly displayed e.g. using PowerDVDUltra.
I hope this method works for you. You can contact me if you have problems.
Schmendrick |
Hi I got quite excited when I read this post since it seemed to be a way to convert the DVB-T broadcasts in NZ which use H.264 video and AAC-HE LATM audio to something more accessible. I used tsmuxer to separate the streams but I cannot even play the AAC files in winamp, let alone output them as wav files. This is winamp 5.54
Winamp reports the right length in time but as soon as I press play it stops.
Are you able to try your process on files on this page and report your experiences?
http://www.geekzone.co.nz/Fossie/4877
Thanks