[BAG] Implement topic-specific extraction (extract topics) #31
Description
Summary
The robocodec extract topics command does not work for BAG format files.
Current Behavior
$ robocodec extract topics input.bag output.bag "/topic1,/topic2"
Error: Topic-specific extraction requires format-specific message iteration. This feature is not yet implemented. Use the convert command for full file copying.
Expected Behavior
Should extract only the specified topics from the BAG file and write them to a new BAG file.
Use Case
- Extract specific sensor data from multi-topic bag files
- Create topic-specific subsets for analysis
- Filter out irrelevant topics
MCAP Status
This feature works for MCAP files, only BAG format is affected.
Related
- Issue [BAG] Implement partial message extraction (extract messages --count) #30 (partial message extraction)
- Part of BAG feature parity with MCAP