jik jikman wrote: > Some sites say it is pva format, some other say it is pes format and > other say it is ts format without pat/pmt tables. > > What is vdr file format at last? and why we can't record directly in > mpg ( mpeg ps ) format as we can do in windows? Some clarifications about terms AFAIK: Elementary Stream (ES): Video stream, audio stream or similar data stream. Packetized Elementary Stream (PES): ES cut into a sequence of packets. Since all PES packets of one ES share one stream id, its possible to mix PES packets of several ES streams into one PES stream. PES also adds information for time synchronization of the streams. Transport Stream (TS): Mainly used for live streams. Another packet stream that packs several PES streams, each containing only one ES stream, into small packets for transport. The streams are separated by the packet identifier (PID). TS also adds data packets describing the contents of the stream. Program Stream (PS): The classic mpeg2 video file format. PS packs several PES packets of different ES streams into 'packs'. Also, PS has info headers describing the contents of the PS. PES is not meant to be a file format, its just an internal stream format. PES or similar formats are widely used by PVRs because data of TS streams can easily be extracted into PES streams. However, PES as file format has several disadvantages: - No content information headers, streams may appear or disappear at any time. No way to tell exactly whats in it without scanning the whole file. - Strange A/V syncing, like audio starting a second earlier than video, or audio and video not having the same length. - Discontinuities. There may be gaps of several minutes in video and audio data (cut out). No way to tell how long a video is without scanning the whole file. Converting from PES to a well-formatted PS is a tough job, thats why there are special programs doing that job. Directly recording into PS wont make it easier. Cheers, Udo
