HDV is a high-definition format that is often marketed as the HD evolution of DV formats, but in fact is derived from MPEG-2. (This codec doesn't come pre-installed in Mac computers.)
HDV media comes inside a QuickTime mov container, with one video track and one or several audio tracks.
HDV is almost identical to XDCAM, and sometimes Treasured cannot determine which of them is actually detected.
Repairability
HDV media is repaired without major problem. A sample of a good file is often needed.
It is often necessary, and always helpful, to have a good HDV file similarly encoded. Even if the file contains only a few frames, the fact that it was encoded with the exact settings of the damaged file will provide useful information:
This information can be guessed from a damaged file, but through a very lengthy trial-and-error iterative process.
How to repair a corrupt HDV movie
The easiest way is certainly to ask our Movie Repair Service to do it for you.
But for those who can program, here you have a few tips:
Techniques used are:
Video track has a 'hvdx' codec fourcc (where x can take values from 1 to 7) and is organized in keyframes and inter-frames. HDV frames are not stored in playback order, so there is a ctts table that specifies the offset between decode time and display time.
Note that we also find two tables called cslg and sdtp (sample dependencies) but these are optional: the movie works perfectly without them. In repairs we usually don't bother with recreating those tables.
Audio tracks often come in raw PCM 'sowt' of 'twos' formats, for example 48kHz stereo 16 bits.
Repair process consists of reindexing video frames. Note that as 'hdv4' is not available as compressor, the repaired file has to be bootstrapped from a valid one.
Frame reordering is possible if the pattern is predictable. Otherwise, the result will be shaky.
Audio scraping can also cause some problems. Sometimes the audio has some overlapping between frames, thus requiring a special scraping process.