First about the video:
For movies, DVD-NTSC uses the "2: 3Pull-Up" method when storing videos to convert 24 frames of video into 30 frames of video, but the playback of 24 frames of video and converted 30 frames of video The time is 1 second. The video made by Pal was loaded directly into the DVD without any processing, so the frame speed of the Pal system was 25 frames, so the original movie video was played 24 frames per second, and the DVD made by Pal played every second. After 25 frames, under the premise that the total number of frames is certain, the video made by Pal will actually shorten the playing time by 4%!
This shows that the same 100-minute movie is still 100 minutes on NTSC, and 96 minutes on PAL, which means that the PAL DVD will be faster than the same film made by NTSC 1 / twenty four. When converting time, NTSC time X 24/25 = PAL time
Second about audio:
Since PAL video is shorter than the original film, the sound must be shorter in order to synchronize the sound with the video. How does the sound become shorter? Naturally, the playback speed of the sound is accelerated, and the effect can be analogized to the fast playback of the tape. The result is that the pitch of the sound will become higher. Pal's audio is such a "fast playback" process, but the speed of this sound changes only 4%, and the tone distortion will not be particularly serious.
Then if the shorter PAL audio is integrated into the longer NTSC video, in order to achieve the synchronization of sound and picture, the sound must be slowed down by 4%. Since this process requires re-sampling, it will cause a certain amount of sound quality. Decline, which explains why PAL audio tracks should not be integrated with NTSC video.
supplement:
After further research, while changing the speed of the sound, it can compensate for the tone of the sound to make it sound undistorted. There are free software that can do this, but this process is also lossy. As for how harmful it is to sound quality, it's a matter of opinion.
PAL and NTSC system conversion problems:
1.The PAL system records 25 frames per second;
2.The NTSC system records 30 frames per second; (the scanning lines of the two systems are also different);
3. DV format is neither PAL nor NTSC, but it is indeed divided into two versions: 25 frames / second and 30 frames / second;
4. Through the lens, the TRV-900 made of PAL records 25 frames per second, while the TRV-900 made of NTSC records 30 frames per second;
5. From the digital port (1394 port), TRV-900 (the same for other digital cameras) can record 25 frames / second signal, or 30 frames / second;
6. From the analog input port, TRV-900 can only record the same analog signal as the camera system (PAL system or NTSC system);
7. If you play a DV shot with a PAL camera in an NTSC TRV-900, it will output a non-standard 25-frame / second signal with NTSC3.58 color coding. Most TV sets play well, but the VCR cannot record. If output through the digital port (1394 port), it will output the standard PAL version of DV signal;
8. On the contrary, if you play a DV tape recorded in NTSC format in a PAL TRV-900 camera, it will output a non-standard 30 frame / second signal with NTSC4.43 or PAL color coding (Depending on the camera's menu settings). Most TV sets play well, but the VCR cannot record. If it is output through the digital port (1394 port), it will output the standard NTSC DV signal;
9. No camera can convert the number of frames (that is, the number of frames per second) or the scanning line of each frame. This is the key to understanding the problem. When the camera meets other standards, it needs different crystal oscillators to process different signals (3.58 (NTSC) or 4.43 (PAL and NTSC4.43)). But the camera can only have one crystal oscillator;
10. TRV900 will record still images from the PC card port in its own format. That is, if I put a DV tape recorded in NTSC format in a PAL camera and add a few seconds of video from a JEPG format file, then these few seconds of video will be recorded in PAL format.
If you record or play back through IEEE-1394, then you are just performing a pure digital file transfer. Therefore, there is no format conversion problem. If it was originally made in PAL, it will still be made in PAL after copying. If it was originally made by NTSC, it will still be made by NTSC after copying. No matter what type of camera you use.
If you have an analog signal of one system and want to convert it to another system, you need a special image conversion box. If you have a digital DV signal in one format and want to convert it to a DV signal in another format, you can use software to convert it.
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