Difference between revisions of "Private:mtv issues"
From NMSL
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== MPE, and MPE-FEC sections are not being picked up by dvbSAM == | == MPE, and MPE-FEC sections are not being picked up by dvbSAM == | ||
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| + | '''Current Status:''' | ||
| + | *Bug FIXED | ||
'''The Bug: ''' | '''The Bug: ''' | ||
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'''Theory of why this is happening: ''' | '''Theory of why this is happening: ''' | ||
| − | *There is some semantic error in the code, possibly very small | + | *There is some semantic error in the code, possibly very small. |
*I believe that dvbSAM is throwing out some TS packets which happen to include the MPE/MPE-FEC header information which causes the entire section of data to be discarded. | *I believe that dvbSAM is throwing out some TS packets which happen to include the MPE/MPE-FEC header information which causes the entire section of data to be discarded. | ||
*The fact that there are some bursts which are perfect suggests that all the MPE and MPE-FEC sections are being generated correctly. And this in turn would also suggest that packing MPE, MPE-FEC, and TS packets are done correctly. | *The fact that there are some bursts which are perfect suggests that all the MPE and MPE-FEC sections are being generated correctly. And this in turn would also suggest that packing MPE, MPE-FEC, and TS packets are done correctly. | ||
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*Analyzed Burst::enc_mpe(), all mpe sections seem logically generated | *Analyzed Burst::enc_mpe(), all mpe sections seem logically generated | ||
*Analyzed Burst::enc_mpe_fec(), all mpe-fec sections seem logically generated | *Analyzed Burst::enc_mpe_fec(), all mpe-fec sections seem logically generated | ||
| − | *Analyzed Burst::enc_ts(), all ts sections seem logically generated | + | '''EDIT:'''*Analyzed Burst::enc_ts(), all ts sections '''DOES NOT''' seem logically generated |
| − | *Created file containing hex dump of the burst being passed to Transmitter using Burst::dump_ts(). I viewed the TS file using dvbSAM to pick out missing sections in the burst. Then I looked into the hex dump for the TS packets containing the MPE/MPE-FEC section preceding the missing section, the missing section, and the section proceeding the missing section. All sections | + | *Created file containing hex dump of the burst being passed to Transmitter using Burst::dump_ts(). I viewed the TS file using dvbSAM to pick out missing sections in the burst. Then I looked into the hex dump for the TS packets containing the MPE/MPE-FEC section preceding the missing section, the missing section, and the section proceeding the missing section. All sections were found in the hex dump. '''The TS header seemed incorrect; some had 4 bytes, but should have 5.''' |
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Latest revision as of 11:09, 15 July 2010
MPE, and MPE-FEC sections are not being picked up by dvbSAM
Current Status:
- Bug FIXED
The Bug:
- When the program is run using the STAND algorithm and the TS file is generated, dvbSAM has determined that there are entire MPE and/or MPE-FEC sections missing inside some bursts. (Maybe some are half missing as well, but I have not verified this claim)
- There does not seem to be a pattern in determining which burst will be missing sections. Some bursts will be 100% complete whereas some bursts will be missing at least one section of data.
- The MPE and/or MPE-FEC sections missing also seem to be randomly determined.
- Unfortunately a different TS file gets generated even if you run the program with the same configurations. This means that dvbSAM shows different #of packets per burst, different #of bytes corrected by MPE-FEC, etc. I produced at least 5 different TS files using the same configurations, none of which contained identical burst sequences.
Perfect burst:
Problematic burst:
Section preceding missing section:
Section proceeding missing section:
Theory of why this is happening:
- There is some semantic error in the code, possibly very small.
- I believe that dvbSAM is throwing out some TS packets which happen to include the MPE/MPE-FEC header information which causes the entire section of data to be discarded.
- The fact that there are some bursts which are perfect suggests that all the MPE and MPE-FEC sections are being generated correctly. And this in turn would also suggest that packing MPE, MPE-FEC, and TS packets are done correctly.
Steps Taken:
- Analyzed Burst::enc_mpe(), all mpe sections seem logically generated
- Analyzed Burst::enc_mpe_fec(), all mpe-fec sections seem logically generated
EDIT:*Analyzed Burst::enc_ts(), all ts sections DOES NOT seem logically generated
- Created file containing hex dump of the burst being passed to Transmitter using Burst::dump_ts(). I viewed the TS file using dvbSAM to pick out missing sections in the burst. Then I looked into the hex dump for the TS packets containing the MPE/MPE-FEC section preceding the missing section, the missing section, and the section proceeding the missing section. All sections were found in the hex dump. The TS header seemed incorrect; some had 4 bytes, but should have 5.
