fate/mp3: specify the number of output samples instead of filesize

This is not dependent on the output format.

tests/fate/mp3.mak

@@ -3,27 +3,27 @@ fate-mp3-float-conf-compl: CMD = pcm -acodec mp3float -i $(TARGET_SAMPLES)/mp3-c
 fate-mp3-float-conf-compl: REF = $(SAMPLES)/mp3-conformance/compl_2.pcm
 
 FATE_MP3 += fate-mp3-float-conf-he_32khz
-fate-mp3-float-conf-he_32khz: CMD = pcm -acodec mp3float -i $(TARGET_SAMPLES)/mp3-conformance/he_32khz.bit -fs 343296
+fate-mp3-float-conf-he_32khz: CMD = pcm -acodec mp3float -i $(TARGET_SAMPLES)/mp3-conformance/he_32khz.bit -af atrim=end_sample=171648
 fate-mp3-float-conf-he_32khz: REF = $(SAMPLES)/mp3-conformance/he_32khz.pcm
 
 FATE_MP3 += fate-mp3-float-conf-he_44khz
-fate-mp3-float-conf-he_44khz: CMD = pcm -acodec mp3float -i $(TARGET_SAMPLES)/mp3-conformance/he_44khz.bit -fs 942336
+fate-mp3-float-conf-he_44khz: CMD = pcm -acodec mp3float -i $(TARGET_SAMPLES)/mp3-conformance/he_44khz.bit -af atrim=end_sample=471168
 fate-mp3-float-conf-he_44khz: REF = $(SAMPLES)/mp3-conformance/he_44khz.pcm
 
 FATE_MP3 += fate-mp3-float-conf-he_48khz
-fate-mp3-float-conf-he_48khz: CMD = pcm -acodec mp3float -i $(TARGET_SAMPLES)/mp3-conformance/he_48khz.bit -fs 343296
+fate-mp3-float-conf-he_48khz: CMD = pcm -acodec mp3float -i $(TARGET_SAMPLES)/mp3-conformance/he_48khz.bit -af atrim=end_sample=171648
 fate-mp3-float-conf-he_48khz: REF = $(SAMPLES)/mp3-conformance/he_48khz.pcm
 
 FATE_MP3 += fate-mp3-float-conf-hecommon
-fate-mp3-float-conf-hecommon: CMD = pcm -acodec mp3float -i $(TARGET_SAMPLES)/mp3-conformance/hecommon.bit -fs 133632
+fate-mp3-float-conf-hecommon: CMD = pcm -acodec mp3float -i $(TARGET_SAMPLES)/mp3-conformance/hecommon.bit -af atrim=end_sample=33408
 fate-mp3-float-conf-hecommon: REF = $(SAMPLES)/mp3-conformance/hecommon.pcm
 
 FATE_MP3 += fate-mp3-float-conf-si
-fate-mp3-float-conf-si: CMD = pcm -acodec mp3float -i $(TARGET_SAMPLES)/mp3-conformance/si.bit -fs 269568
+fate-mp3-float-conf-si: CMD = pcm -acodec mp3float -i $(TARGET_SAMPLES)/mp3-conformance/si.bit -af atrim=end_sample=134784
 fate-mp3-float-conf-si: REF = $(SAMPLES)/mp3-conformance/si.pcm
 
 FATE_MP3 += fate-mp3-float-conf-si_block
-fate-mp3-float-conf-si_block: CMD = pcm -acodec mp3float -i $(TARGET_SAMPLES)/mp3-conformance/si_block.bit -fs 145152
+fate-mp3-float-conf-si_block: CMD = pcm -acodec mp3float -i $(TARGET_SAMPLES)/mp3-conformance/si_block.bit -af atrim=end_sample=72576
 fate-mp3-float-conf-si_block: REF = $(SAMPLES)/mp3-conformance/si_block.pcm
 
 FATE_MP3 += fate-mp3-float-extra_overread