[FFmpeg-devel] [PATCH] extract bit rate calculation into separate function

[Robert Krüger]

Hi,

On 11.11.2009, at 11:23, Carl Eugen Hoyos wrote:

> Hi!
>
> Robert Kr?ger <krueger <at> signal7.de> writes:
>
>>>> +/**
>>>> + * Calculates the bit rate of a stream
>>>> + *
>>>> + * @ctx AVCodecContext of the stream
>>>> + * @return bit rate in bits per second
>>>> + */
>>>
>>> this belongs in a header
>>>
>> moved to header avformat.h and changed name to av_codec_get_bitrate
>> because that seems to be the naming convention for exposed functions 
>> (?)
>
> You certainly cannot have a declaration in libavformat/avformat.h  
> and the code
> in libavcodec/utils.c (the different directories are a hint).
>

sorry, embarrassing mistake. Updated patch attached.

Regards,

Robert

Index: libavcodec/avcodec.h
===================================================================
--- libavcodec/avcodec.h	(revision 20511)
+++ libavcodec/avcodec.h	(working copy)
@@ -3444,6 +3444,14 @@
   */
  int av_get_bits_per_sample_format(enum SampleFormat sample_fmt);

+/**
+ * Calculates the bit rate of a stream
+ *
+ * @ctx AVCodecContext of the stream
+ * @return Bit rate in bits per second or 0 if it could not be  
determined
+ */
+int av_get_bitrate(AVCodecContext *ctx);
+
  /* frame parsing */
  typedef struct AVCodecParserContext {
      void *priv_data;
Index: libavcodec/utils.c
===================================================================
--- libavcodec/utils.c	(revision 20511)
+++ libavcodec/utils.c	(working copy)
@@ -741,6 +741,34 @@
      return NULL;
  }

+int av_get_bitrate(AVCodecContext *ctx)
+{
+    int bitrate;
+    int bits_per_sample;
+
+    switch(ctx->codec_type) {
+    case CODEC_TYPE_VIDEO:
+  	    bitrate = ctx->bit_rate;
+        break;
+    case CODEC_TYPE_AUDIO:
+    	bits_per_sample = av_get_bits_per_sample(ctx->codec_id);
+    	bitrate = bits_per_sample ? ctx->sample_rate * ctx->channels *  
bits_per_sample : ctx->bit_rate;
+        break;
+    case CODEC_TYPE_DATA:
+        bitrate = ctx->bit_rate;
+        break;
+    case CODEC_TYPE_SUBTITLE:
+        bitrate = ctx->bit_rate;
+        break;
+    case CODEC_TYPE_ATTACHMENT:
+        bitrate = ctx->bit_rate;
+        break;
+    default:
+        break;
+    }
+    return bitrate;
+}
+
  void avcodec_string(char *buf, int buf_size, AVCodecContext *enc,  
int encode)
  {
      const char *codec_name;
@@ -813,7 +841,6 @@
              snprintf(buf + strlen(buf), buf_size - strlen(buf),
                       ", q=%d-%d", enc->qmin, enc->qmax);
          }
-        bitrate = enc->bit_rate;
          break;
      case CODEC_TYPE_AUDIO:
          snprintf(buf, buf_size,
@@ -830,57 +857,15 @@
                       ", %s", avcodec_get_sample_fmt_name(enc- 
 >sample_fmt));
          }

-        /* for PCM codecs, compute bitrate directly */
-        switch(enc->codec_id) {
-        case CODEC_ID_PCM_F64BE:
-        case CODEC_ID_PCM_F64LE:
-            bitrate = enc->sample_rate * enc->channels * 64;
-            break;
-        case CODEC_ID_PCM_S32LE:
-        case CODEC_ID_PCM_S32BE:
-        case CODEC_ID_PCM_U32LE:
-        case CODEC_ID_PCM_U32BE:
-        case CODEC_ID_PCM_F32BE:
-        case CODEC_ID_PCM_F32LE:
-            bitrate = enc->sample_rate * enc->channels * 32;
-            break;
-        case CODEC_ID_PCM_S24LE:
-        case CODEC_ID_PCM_S24BE:
-        case CODEC_ID_PCM_U24LE:
-        case CODEC_ID_PCM_U24BE:
-        case CODEC_ID_PCM_S24DAUD:
-            bitrate = enc->sample_rate * enc->channels * 24;
-            break;
-        case CODEC_ID_PCM_S16LE:
-        case CODEC_ID_PCM_S16BE:
-        case CODEC_ID_PCM_S16LE_PLANAR:
-        case CODEC_ID_PCM_U16LE:
-        case CODEC_ID_PCM_U16BE:
-            bitrate = enc->sample_rate * enc->channels * 16;
-            break;
-        case CODEC_ID_PCM_S8:
-        case CODEC_ID_PCM_U8:
-        case CODEC_ID_PCM_ALAW:
-        case CODEC_ID_PCM_MULAW:
-        case CODEC_ID_PCM_ZORK:
-            bitrate = enc->sample_rate * enc->channels * 8;
-            break;
-        default:
-            bitrate = enc->bit_rate;
-            break;
-        }
          break;
      case CODEC_TYPE_DATA:
          snprintf(buf, buf_size, "Data: %s", codec_name);
-        bitrate = enc->bit_rate;
          break;
      case CODEC_TYPE_SUBTITLE:
          snprintf(buf, buf_size, "Subtitle: %s", codec_name);
-        bitrate = enc->bit_rate;
          break;
      case CODEC_TYPE_ATTACHMENT:
          snprintf(buf, buf_size, "Attachment: %s", codec_name);
-        bitrate = enc->bit_rate;
          break;
      default:
          snprintf(buf, buf_size, "Invalid Codec type %d", enc- 
 >codec_type);
@@ -894,6 +879,7 @@
              snprintf(buf + strlen(buf), buf_size - strlen(buf),
                       ", pass 2");
      }
+    bitrate = av_get_bitrate(enc);
      if (bitrate != 0) {
          snprintf(buf + strlen(buf), buf_size - strlen(buf),
                   ", %d kb/s", bitrate / 1000);