DVCPro50 is a variant of DV codec aimed at professionals and applications like electronic news gathering. It doubles the bit-rate of DV, using 4:2:2 chroma subsampling instead of 4:1:1 in DV.
Unlike DV, DVCPro50 uses dedicated tracks for audio. Common audio formats are: in24 or PCM, usually 48000Hz, up to 8 channels. DVCPro50 is normally found in QuickTime .mov containers, or .dv containers.
DVCPro50 media is repaired without any problem. The quality is excellent.
DVCPro50 bitstream is easy to detect and parse, because it follows a regular data pattern:
- Each frame contains exactly 240000 bytes in NTSC, 288000 in PAL.
- Each frame contains blocks of exactly 12000 bytes (20 in NTSC, 24 in PAL) that begin with 1F xy 00 with x between 0 and 9 (NTSC) or 11 (PAL) and y=3 or 7.
- Furthermore, every 80 bytes exactly, the xy byte is repeated.
To perform a repair, it's necessary first to determine which profile is used.
If you take the 1F 07 00 pattern as reference (beginning of frame), the positions 5, 6, 7 have a value of 0x79.
Position 3 is either 3F or BF.
Position 451 can take several values.
To interpret those values, please refer to ffmpeg source code. The tables are at the end of the file dvdata.h (search for DVprofile)