Differences

This shows you the differences between two versions of the page.

--- ffmpeg:av_read_frame [2007/11/22 16:56] – created deva
+++ ffmpeg:av_read_frame [2007/11/22 17:00] – deva
@@ Line 1: / Line 1: @@
-=====avcodec_decode_video=====
+=====avc_read_frame=====
 ====Overview====
 Defined in ''avformat.h''\\
-Read a transport packet from a media file.\\
+Return the next frame of a stream.\\
-This function is obsolete and should never be used.\\
+The returned packet is valid until the next av_read_frame() or until av_close_input_file() and must be freed with av_free_packet. For video, the packet contains exactly one frame. For audio, it contains an integer number of frames if each frame has a known fixed size (e.g. PCM or ADPCM data). If the audio frames have a variable size (e.g. MPEG audio), then it contains one frame.\\
-Use [[ffmpeg:av_read_frame|av_read_frame()]] instead.
+pkt->pts, pkt->dts and pkt->duration are always set to correct values in AVStream.timebase units (and guessed if the format cannot provided them). pkt->pts can be AV_NOPTS_VALUE if the video format has B frames, so it is better to rely on pkt->dts if you do not
+decompress the payload.
 <code c>
-int av_read_packet(AVFormatContext *s,
+int av_read_frame(AVFormatContext *s,
-                   AVPacket *pkt);
+                  AVPacket *pkt);
 </code>
@@ Line 23: / Line 25: @@
 ====Return value====
-if OK. AVERROR_xxx if error.
+if OK, < 0 if error or end of file.
 ----
 Back to [[ffmpeg:ffmpeg]]