Map Specific PID Streams from MPEG TS Using FFmpeg

This article explains how to identify, select, and map specific Packet Identifier (PID) streams from an MPEG Transport Stream (.ts) using FFmpeg. You will learn how to use ffprobe to locate the PIDs within your file and how to use the ffmpeg command-line tool to map and extract those precise streams into a new output file while preserving or modifying their PID assignments.

Step 1: Identify the PIDs and Stream Indexes

An MPEG Transport Stream contains multiple multiplexed streams (video, audio, subtitles, and metadata), each identified by a unique PID. Before you can map these streams, you must identify their corresponding stream indexes in FFmpeg.

Run the following ffprobe command to inspect your input TS file:

ffprobe -i input.ts

In the output, look for the stream details. They will look similar to this:

Stream #0:0[0x101]: Video: h264 (High) ([27][0][0][0] / 0x001B)
Stream #0:1[0x102](eng): Audio: ac3 ([129][0][0][0] / 0x0081)
Stream #0:2[0x103](spa): Audio: ac3 ([129][0][0][0] / 0x0081)

In this example: * 0:0 is the stream index for the video stream, which has the PID 0x101 (257 in decimal). * 0:1 is the stream index for the English audio stream, which has the PID 0x102 (258 in decimal). * 0:2 is the stream index for the Spanish audio stream, which has the PID 0x103 (259 in decimal).

Step 2: Map the Specific Streams

To extract only the video (0:0) and the English audio (0:1) streams, use the -map option in FFmpeg.

ffmpeg -i input.ts -map 0:0 -map 0:1 -c copy output.ts

• -i input.ts: Specifies the input TS file.
• -map 0:0: Selects the first stream (video with PID 0x101).
• -map 0:1: Selects the second stream (audio with PID 0x102).
• -c copy: Copies the video and audio packets directly without re-encoding, preserving quality and saving CPU resources.

Step 3: Set Specific PIDs in the Output File (Optional)

By default, FFmpeg will assign new, sequential PIDs to the streams in the output TS file. If your playback equipment or software requires the output streams to retain their original PIDs (or use specific custom PIDs), you must use the -streamid option.

The -streamid option maps an output stream index to a specific PID value (in hexadecimal or decimal):

ffmpeg -i input.ts -map 0:0 -map 0:1 -c copy -streamid 0:0x101 -streamid 1:0x102 output.ts

• -streamid 0:0x101: Assigns the PID 0x101 to the first mapped output stream (index 0).
• -streamid 1:0x102: Assigns the PID 0x102 to the second mapped output stream (index 1).